Preheat your oven to 450°F (230°C). Grease an 8-inch round cake pan or line a baking sheet with parchment paper if making individual shortcakes.

In a large bowl, whisk together the flour, granulated sugar, baking powder, and salt until well combined.

Using a pastry cutter, two knives, or your fingertips, work the cold butter into the flour mixture until it resembles coarse crumbs with some pea-sized pieces remaining.

In a small bowl, whisk together the milk, egg, and vanilla. Pour into the flour mixture and stir gently with a fork just until the dough comes together. Be careful not to overmix.

For a single large shortcake: Transfer the dough to the prepared pan and gently spread it evenly. For individual shortcakes: Turn the dough onto a lightly floured surface, pat to 3/4-inch thickness, and cut into 8 rounds using a biscuit cutter. Place on prepared baking sheet.

Sprinkle the top with coarse sugar if using. Bake for 15-18 minutes for individual shortcakes or 20-25 minutes for one large shortcake, until golden brown and a toothpick inserted in the center comes out clean.

While the shortcake is baking, combine the sliced strawberries, sugar, and lemon juice in a bowl. Stir gently and let sit at room temperature for at least 30 minutes to create a sweet strawberry syrup.

In a chilled bowl, beat the heavy cream, powdered sugar, and vanilla until soft peaks form. Be careful not to overbeat.

When the shortcake is cool enough to handle, split it horizontally (if using one large cake) or individual cakes in half. Place the bottom half on a serving plate, top generously with strawberries and their juice, add a dollop of whipped cream, then cap with the top half of the shortcake. Add more berries and cream on top.