Add sliced strawberries to a large bowl. Stir in ⅓ cup sugar and lemon juice. Let sit 20 to 30 minutes, stirring once or twice. Stir in vanilla (optional).

Preheat oven to 425°F (220°C). Line a baking sheet with parchment paper.

In a large bowl, whisk together flour, ¼ cup sugar, baking powder, baking soda, and salt.

Cut cold butter into the flour mixture until it resembles coarse crumbs with a few pea-sized bits.

Whisk buttermilk and egg together, then pour into the bowl. Stir just until a shaggy dough forms.

Turn dough onto a lightly floured surface. Pat into a ¾-inch thick rectangle. Fold in half, pat down, then fold one more time.

Cut into rounds with a 2½ to 3-inch biscuit cutter. Place on prepared baking sheet. Re-roll scraps gently and cut more.

Optional: brush tops lightly with a splash of buttermilk and sprinkle with coarse sugar.

Bake 14 to 16 minutes, until golden. Cool 5 minutes on the pan, then transfer to a rack.

Make whipped cream: whip heavy cream, powdered sugar, vanilla, and salt to medium peaks.

Assemble: split each shortcake, spoon strawberries and syrup over the bottom, add whipped cream, add the top, and finish with more whipped cream and berries.