Preheat the oven to 425°F (220°C). In a large bowl combine the flour, granulated sugar, baking powder, and salt. Cut the cold butter into the dry ingredients using a pastry cutter or your fingertips until the mixture resembles coarse crumbs. Stir in the milk and vanilla just until the dough comes together.

Turn the dough onto a lightly floured surface and gently pat it into a 1-inch thick round. Use a biscuit cutter or a glass rim dipped in flour to cut out six rounds. Place the rounds on a parchment-lined baking sheet, spacing them about 2 inches apart. Bake until the shortcakes are risen and golden brown, about 12 to 15 minutes. Remove from the oven and let cool slightly.

While the shortcakes bake, combine the sliced strawberries with the sugar and lemon juice in a bowl. Toss gently and let the mixture sit at room temperature for at least 15 minutes so the berries release their juices.

In a chilled mixing bowl whip the heavy cream with the powdered sugar and vanilla extract until soft peaks form. Be careful not to overwhip.

To assemble, slice each shortcake in half horizontally. Spoon a generous layer of strawberries and their juices over the bottom half, followed by a dollop of whipped cream. Cap with the top half of the shortcake and add an extra spoonful of berries and cream if desired. Serve immediately.