In a medium bowl, combine the sliced strawberries and granulated sugar. Toss to coat and let sit for about 30 minutes to macerate.

Preheat the oven to 425°F. Line a baking sheet with parchment paper.

In a large bowl, whisk together the flour, baking powder, and salt. Add the cold, cubed butter and use a pastry cutter or your fingers to mix until the mixture resembles coarse crumbs.

Pour in the heavy cream and vanilla extract. Stir until just combined. Do not overmix.

Turn the dough out onto a floured surface and gently knead it a few times until it comes together. Pat the dough into a 1-inch thick rectangle. Cut out rounds using a biscuit cutter or a glass and place them on the prepared baking sheet.

Brush the tops of the shortcakes with milk. Bake for 12-15 minutes, or until golden brown. Remove from the oven and let cool slightly.

To assemble, slice the shortcakes in half horizontally. Spoon some of the macerated strawberries onto the bottom half, add a dollop of whipped cream, and place the top half back on. Serve immediately.