These oven baked Lyonnaise potatoes are a simple, buttery side dish made with just three ingredients. Thinly sliced potatoes and tender onions bake together until the potatoes are soft in the center, with golden, lightly crisp edges and plenty of savory flavor.
This easy potato recipe takes the classic combination of potatoes, onions, and butter and turns it into an oven-baked dish that requires very little hands-on cooking. There’s no need to stand over the stove frying batches of potatoes. The oven does most of the work.
The result is a comforting side dish that pairs beautifully with roast chicken, steak, pork chops, or a traditional Sunday dinner. And with only three everyday ingredients, it’s an excellent recipe to keep on hand when you need something simple and satisfying.
WHAT ARE LYONNAISE POTATOES?
Lyonnaise potatoes are a traditional French potato dish made with sliced potatoes, onions, and butter. The name comes from Lyon, France, where onions are a common ingredient in local cooking.
Traditional Lyonnaise potatoes are usually prepared by cooking the potatoes and onions in a skillet until golden brown.
This oven-baked version uses the same basic ingredients but changes the cooking method. The potatoes soften under a foil covering before finishing uncovered, allowing their edges to turn golden.
The onions become tender and slightly sweet as they cook in the butter, giving the potatoes plenty of flavor without needing a long list of seasonings.
WHY YOU’LL LOVE THESE 3-INGREDIENT LYONNAISE POTATOES
ONLY THREE INGREDIENTS: Potatoes, onions, and salted butter are all you need. There’s no cream, cheese, or complicated seasoning mixture.
EASY OVEN PREPARATION: Once everything is sliced and arranged in the baking dish, the oven handles most of the cooking.
BUTTERY, GOLDEN POTATOES: The potatoes bake until tender, while the uncovered cooking time helps create lightly crisp, golden edges.
PERFECT FOR FAMILY DINNERS: This side dish goes with everything from baked chicken to a hearty beef roast.
BUDGET-FRIENDLY: Potatoes and onions are inexpensive ingredients that can turn into a generous side dish for six people.
I love how a simple combination of ingredients can produce a side dish with so much flavor. The onions add a lovely sweetness, while the salted butter gives the potatoes a rich, savory finish.
OVEN BAKED LYONNAISE POTATOES INGREDIENTS
You’ll need:
- 2 pounds Yukon Gold potatoes, washed and sliced into ⅛-inch-thick rounds
- 2 large yellow onions, peeled, halved, and thinly sliced
- 6 tablespoons salted butter, divided into 2 tablespoons and 4 tablespoons
That’s the complete ingredient list. Using salted butter helps season the potatoes without adding a fourth ingredient.
WHICH POTATOES ARE BEST FOR LYONNAISE POTATOES?
Yukon Gold potatoes are an excellent choice for this oven-baked recipe.
They have a naturally buttery flavor and a creamy texture that works well with the onions. They also hold their shape better than some starchier potatoes, so the slices are less likely to fall apart when served.
You can leave the thin skins on or peel the potatoes before slicing. Either method works.
Try to choose potatoes that are similar in size. This makes it easier to cut uniform rounds, helping everything cook at approximately the same rate.
WHY USE YELLOW ONIONS?
Yellow onions become mild and sweet as they cook, making them a good choice for Lyonnaise potatoes.
Two large onions might seem like a lot when you’re slicing them, but they’ll soften and shrink considerably in the oven.
The onions are an important part of this dish, so don’t reduce the amount too much. You want some tender onion mixed into every serving.
WHY SALTED BUTTER WORKS BEST
Salted butter adds richness and provides the seasoning in this three-ingredient version.
You’ll use part of the butter to begin cooking the onions and the remainder to coat the potato slices.
As everything bakes, the butter combines with the natural moisture from the vegetables, helping the potatoes cook evenly while giving them a delicious buttery flavor.
HOW TO MAKE OVEN BAKED LYONNAISE POTATOES
These easy Lyonnaise potatoes start with thinly sliced vegetables and finish in the oven. The important steps are keeping the potato slices uniform, covering the dish during the first part of baking, and allowing enough uncovered cooking time for browning.
Here’s how to make them.
STEP ONE: PREHEAT THE OVEN
Preheat your oven to 400°F.
Have a 9×13-inch baking dish ready. Make sure your baking dish is oven-safe at this temperature.
Position an oven rack in the center of the oven so the potatoes receive even heat.
STEP TWO: PREPARE THE POTATOES
Wash the Yukon Gold potatoes thoroughly and remove any damaged spots.
Slice the potatoes into rounds approximately ⅛ inch thick. A sharp knife works well, but a mandoline slicer makes it easier to achieve consistent thickness.
Try not to cut the slices too thick. Thick potatoes will take longer to soften and may still be firm when the onions are fully cooked.
Pat the sliced potatoes dry with a clean kitchen towel or paper towels if they have excess moisture.
PRO TIP:
If you’re using a mandoline, always use the safety guard to protect your fingers. The potatoes need to be thin, but they don’t need to be paper-thin.
STEP THREE: SLICE THE ONIONS
Peel the yellow onions, cut them in half from top to bottom, and slice each half into thin strips.
Aim for slices around ⅛ inch thick.
Keeping the onions thin helps them soften during baking and prevents large pieces from remaining firm between the potatoes.
Separate the onion slices gently with your fingers so they can cook more evenly.
STEP FOUR: START COOKING THE ONIONS
Place 2 tablespoons of salted butter in the 9×13-inch baking dish.
Put the dish in the preheated oven for two to three minutes, just until the butter melts.
Carefully remove the dish and add the sliced onions. Toss gently to coat them with the melted butter.
Spread the onions across the bottom of the baking dish.
Return the uncovered dish to the oven for approximately 12 to 15 minutes, stirring once halfway through.
The onions should begin to soften and turn slightly golden around the edges.
They don’t need to become deeply caramelized at this stage because they’ll continue cooking with the potatoes.
STEP FIVE: ADD THE POTATOES
While the onions are cooking, melt the remaining 4 tablespoons of salted butter.
Place the sliced potatoes into a large mixing bowl and pour the melted butter over them.
Gently toss until the slices are evenly coated. Separate any potatoes that are sticking together.
Remove the baking dish from the oven and carefully combine the potatoes with the softened onions.
Spread everything into a fairly even layer, making sure the onions are distributed throughout the dish.
Some potatoes will overlap, which is perfectly fine.
STEP SIX: COVER AND BAKE
Cover the baking dish tightly with aluminum foil.
Place it in the oven and bake for 35 to 40 minutes.
The foil traps steam, helping the sliced potatoes soften before the tops begin to brown.
After 35 minutes, carefully lift one corner of the foil, keeping your hands away from the escaping steam.
Test a potato near the center with the tip of a sharp knife.
It should be nearly tender, with only a little resistance remaining.
PRO TIP:
Don’t remove the foil too early. The covered baking time is what helps the center potatoes become tender without drying out the top layer.
STEP SEVEN: BAKE UNTIL GOLDEN
Remove the aluminum foil and gently turn a few of the top potato slices to expose different edges.
Return the uncovered baking dish to the oven.
Continue baking for another 20 to 25 minutes, or until the potatoes are fully tender and have golden brown spots on top.
The onions should be soft, with some darker golden edges.
If the potatoes are tender but you want a little more color, you can broil them for one to two minutes. Watch closely because the thin onion pieces can brown very quickly.
STEP EIGHT: REST AND SERVE
Remove the baked Lyonnaise potatoes from the oven.
Allow the dish to rest for approximately five minutes before serving.
This gives the hot butter a little time to settle and makes the potatoes easier to lift from the baking dish.
Serve warm, making sure every portion includes some of the tender, buttery onions.
TIPS FOR PERFECT OVEN BAKED LYONNAISE POTATOES
Making this recipe is straightforward, but a few small details can make a difference in the finished potatoes.
SLICE THE POTATOES EVENLY: Uniform slices cook at the same rate. If some are very thick while others are thin, you’ll end up with a mixture of soft and undercooked potatoes.
USE A LARGE ENOUGH BAKING DISH: A 9×13-inch dish gives two pounds of potatoes enough room to cook without being packed into a very deep layer. A smaller dish may require additional baking time.
DON’T SKIP THE COVERED BAKING TIME: Covering the potatoes allows the steam to soften them. Without this step, the exposed potato slices could brown before the center finishes cooking.
COAT THE POTATOES WITH BUTTER: Give the potato slices a good toss before adding them to the dish. The butter helps prevent dry spots and encourages browning during the final stage.
WATCH THE ONIONS: Thin onions can become dark around the edges. A little browning adds flavor, but burnt onions can give the entire dish a bitter taste.
SERVE WHILE WARM: These potatoes have the best texture shortly after baking. The edges will gradually soften as the dish sits.
HOW TO GET CRISPIER EDGES
For potatoes with more golden edges, make sure the dish is uncovered during the final 20 to 25 minutes.
You can also use a wide, shallow baking dish rather than a deep casserole dish.
The more potato surface exposed to the oven’s heat, the more opportunity there is for browning.
Keep in mind that this baked version will have soft, buttery potatoes with lightly crisp edges rather than the all-over crispness of individually pan-fried slices.
LYONNAISE POTATOES SUBSTITUTIONS AND VARIATIONS
One of the best things about this recipe is how easy it is to adjust while keeping the same three-ingredient combination.
POTATOES: Yukon Gold potatoes are recommended, but red potatoes are another good choice. They have a waxy texture that helps the slices maintain their shape. Russet potatoes can also work, although they’re starchier and may break apart more easily.
ONIONS: Sweet onions can replace yellow onions if you prefer a milder flavor. Red onions are another option and will give the finished dish a slightly different appearance.
BUTTER: Unsalted butter can be used in place of salted butter, but the finished dish will have less seasoning. For a dairy-free variation, substitute a salted plant-based butter suitable for baking.
THICKER POTATOES: If you prefer slices closer to ¼ inch thick, plan on increasing the covered baking time. Always check the center potatoes for tenderness before uncovering the dish.
WHAT TO SERVE WITH LYONNAISE POTATOES
These buttery oven-baked potatoes make a delicious side dish for both everyday dinners and special occasions.
They pair especially well with roasted chicken. The soft onions and golden potatoes are a great match for chicken with crispy skin.
For a hearty meal, serve them alongside pot roast, beef stew, or a juicy steak. The potatoes soak up the savory juices from the meat beautifully.
Pork chops and pork tenderloin are also excellent options. Their mild flavor works well with the richness of the butter and cooked onions.
If you’re planning a holiday dinner, these potatoes make a nice alternative to mashed potatoes or a creamy potato casserole.
For a lighter meal, pair them with roasted vegetables, steamed green beans, asparagus, or a crisp green salad.
The potatoes already have plenty of buttery flavor, so simple vegetables are a good choice.
HOW TO STORE OVEN BAKED LYONNAISE POTATOES
These potatoes are best enjoyed fresh from the oven, but leftovers can be stored and reheated.
MAKE AHEAD
You can slice the onions up to a day in advance and refrigerate them in an airtight container.
Potatoes are best sliced shortly before baking because the cut surfaces can turn brown when exposed to air.
If needed, peeled and sliced potatoes can be kept submerged in cold water in the refrigerator for up to 24 hours.
Drain them thoroughly and pat them dry before combining with the butter.
IN THE FRIDGE
Allow leftover potatoes to cool slightly, then transfer them to an airtight container.
Refrigerate within two hours of cooking and store for up to three to four days.
The potatoes will become softer during storage, but they’ll still have their buttery onion flavor.
IN THE FREEZER
Freezing isn’t recommended for the best texture.
Cooked potato slices can become watery or grainy after thawing, especially when they’ve been baked with onions.
If you decide to freeze leftovers, place them in a freezer-safe container and use within two months for the best quality.
REHEATING
For the best results, reheat the potatoes in a 375°F oven for approximately 15 to 20 minutes, or until heated through.
Spread them in a shallow baking dish so they warm evenly.
You can also reheat individual portions in a skillet over medium-low heat. This is a good way to bring back some of the browned edges.
The microwave works when you’re short on time, although the potatoes will be softer.
FREQUENTLY ASKED QUESTIONS
Do I need to boil the potatoes before baking?
No. The potatoes go into the oven raw for this recipe.
Slicing them thinly and covering the baking dish allows them to cook through without boiling first.
Should I peel the potatoes?
Peeling is optional.
Yukon Gold potatoes have thin skins that become tender during baking. If you prefer a smoother texture, peel them before slicing.
Can I make Lyonnaise potatoes without a skillet?
Yes. This recipe uses a baking dish for both the onions and potatoes, so there’s no need to fry anything on the stovetop.
Why are my potatoes still hard?
The potato slices may be too thick, the baking dish may be overcrowded, or the covered cooking time may have been too short.
Cover the dish again and continue baking in five- to ten-minute intervals until the center potatoes are tender.
Why didn’t my potatoes turn golden brown?
The potatoes may have been covered for too long or may have excess moisture.
Once they’re tender, remove the foil and allow enough uncovered baking time for the surfaces to dry and brown.
Can I double this recipe?
Yes. Use two 9×13-inch baking dishes rather than piling all the potatoes into one deep dish.
If baking both dishes at once, rotate their positions during cooking and allow extra time if needed.
Are Lyonnaise potatoes the same as scalloped potatoes?
No. Scalloped potatoes are typically baked with milk or cream to create a creamy sauce.
Lyonnaise potatoes use onions and butter, giving them a different flavor and texture.
OVEN BAKED 3-INGREDIENT LYONNAISE POTATOES RECIPE
Ingredients
- 2 pounds Yukon Gold potatoes sliced into ⅛-inch rounds
- 2 large yellow onions halved and thinly sliced
- 6 tablespoons salted butter divided
Instructions
- Wash the potatoes and slice them into uniform ⅛-inch rounds. Peel them first if desired.
- Peel, halve, and thinly slice the yellow onions.
- Place 2 tablespoons of butter in a 9×13-inch baking dish and melt in the oven for two to three minutes.
- Add the sliced onions, toss with the butter, and bake uncovered for 12 to 15 minutes, stirring halfway through.
- Melt the remaining 4 tablespoons of butter. Toss the sliced potatoes with the melted butter in a large bowl.
- Remove the baking dish from the oven. Add the potatoes and gently combine them with the softened onions. Spread into an even layer.
- Cover tightly with aluminum foil and bake for 35 to 40 minutes, until the potatoes are nearly tender.
- Remove the foil, gently turn some of the top slices, and continue baking uncovered for 20 to 25 minutes, until tender and golden brown.
- Remove from the oven and allow the potatoes to rest for five minutes before serving warm.
Notes
- Slice the potatoes evenly to help them cook at the same rate.
- Salted butter provides the seasoning while keeping the recipe to three ingredients.
- Don't skip the covered baking stage, which allows the potatoes to soften.
- Baking times may vary depending on the thickness of the slices and the baking dish.
- For additional browning, broil for one to two minutes at the end, watching closely.
- Refrigerate leftovers in an airtight container for up to four days.
These oven baked Lyonnaise potatoes are an easy way to turn a few basic ingredients into a warm, satisfying side dish. With tender potato slices, sweet onions, and plenty of buttery flavor, they’re a wonderful addition to weeknight dinners and holiday meals alike. Serve them straight from the oven while the edges are still golden and the onions are soft.
