Macerate the strawberries: In a medium bowl, combine sliced strawberries with sugar. Add lemon juice and vanilla if using. Stir, then let sit at room temperature for 20–30 minutes until the berries release their juices.

Heat the oven: Preheat to 400°F (200°C). Line a baking sheet with parchment paper.

Mix dry ingredients: In a large bowl, whisk flour, sugar, baking powder, and salt. This helps evenly distribute the leavening.

Cut in the butter: Add cold butter cubes to the flour mixture. Use a pastry cutter or your fingertips to work the butter in until you have pea-sized bits. Cold butter is key for flaky, tender shortcakes.

Add wet ingredients: In a small bowl, whisk heavy cream, egg, and vanilla. Pour into the flour mixture and gently fold just until the dough comes together. If it seems dry, add an extra tablespoon of cream at a time. Do not overmix.

Shape the dough: Turn the dough onto a lightly floured surface. Pat into a 3/4-inch thick round. Use a 2.5–3-inch cutter to cut shortcakes. Gather scraps and gently press again to cut remaining pieces.

Bake: Place shortcakes on the sheet, about 2 inches apart. Brush tops with a little cream and sprinkle with coarse sugar if you like. Bake 12–15 minutes, until golden on top and set in the center. Cool on a rack.

Whip the cream: In a chilled bowl, beat heavy cream, powdered sugar, vanilla, and a pinch of salt to soft peaks. It should be smooth and spreadable, not stiff.

Assemble: Split each shortcake horizontally with a serrated knife. Spoon strawberries and their juices over the bottom half, add a generous dollop of whipped cream, then cap with the top half. Add more berries and cream on top if desired. Serve right away.