Combine the sliced strawberries, sugar, and optional lemon juice in a bowl. Stir gently and let them stand at room temperature for 20–30 minutes, stirring once or twice, until glossy juices collect.

Heat the oven to 425°F (220°C) and line a baking sheet with parchment. Whisk the flour, sugar, baking powder, and salt together in a large bowl.

Cut the cold butter into the dry ingredients with a pastry blender or your fingertips until coarse crumbs form, leaving a few pea-sized pieces. Stir in the cold cream or milk and vanilla just until a soft dough comes together.

Turn the dough onto a lightly floured surface and pat it to about 3/4-inch thickness. Cut 8 rounds or divide the dough into 8 rough portions and shape them by hand.

Transfer the shortcakes to the prepared baking sheet. Brush the tops with a little cream and sprinkle with sugar if desired, then bake for 15–18 minutes until puffed and lightly golden.

Beat the cold whipping cream, sugar, and vanilla to medium or stiff peaks, stopping before the cream becomes grainy. Cool the shortcakes for about 5–10 minutes.

Split each shortcake horizontally and spoon strawberries and their juices over the bottom half. Add whipped cream, replace the top, and finish with more berries and cream.