In a medium bowl, combine the sliced strawberries, granulated sugar, and chopped basil. Gently mix and let it sit for about 30 minutes to allow the strawberries to macerate and release their juices.
Preheat your oven to 425°F (220°C).
In a large mixing bowl, whisk together flour, baking powder, and salt. Add the cold, cubed butter and use a pastry cutter or your fingers to incorporate it until the mixture resembles coarse crumbs.
In a separate bowl, mix heavy cream and vanilla extract. Gradually add this mixture to the flour mixture and stir until just combined. Be careful not to overmix.
Turn the dough out onto a floured surface and gently knead it a few times until it comes together. Pat it into a 1-inch thick rectangle, then cut it into rounds using a biscuit cutter.
Place the shortcake rounds on a baking sheet lined with parchment paper. Bake for 12-15 minutes or until golden brown. Allow them to cool for 5 minutes on the baking sheet before transferring to a wire rack to cool completely.
To assemble the shortcakes, slice each shortcake in half. Spoon the macerated strawberries onto the bottom half, add a dollop of mascarpone cheese, then place the top half over it.
Serve immediately, garnishing with additional strawberries and basil on top if desired.
Notes
Serve immediately for the best texture and flavor.