01 - Preheat the oven to 400°F. Line a muffin tin with paper liners or lightly grease with butter.
02 - In a large bowl, whisk together the flour, sugar, baking powder, and salt until evenly combined.
03 - Add the cold cubed butter to the flour mixture. Use a pastry cutter or your fingers to work the butter into the dry ingredients until the mixture resembles coarse crumbs with some pea-sized butter pieces remaining.
04 - In a small bowl, whisk together the milk, beaten egg, and vanilla extract until fully incorporated.
05 - Pour the wet ingredients into the flour mixture. Stir gently with a spatula or wooden spoon just until the dough comes together. Be careful not to overmix—small lumps are fine.
06 - Divide the dough evenly among the 6 prepared muffin cups. Bake for 16 to 18 minutes, until the tops are lightly golden and a toothpick inserted into the center comes out clean. Cool completely in the pan.
07 - While the shortcakes bake and cool, combine the sliced strawberries with sugar and lemon juice in a medium bowl. Toss gently to coat. Let sit at room temperature for at least 15 minutes, stirring occasionally, until the berries release their juices and become syrupy.
08 - Pour the chilled heavy cream into a clean mixing bowl. Add the powdered sugar and vanilla. Beat with an electric mixer on medium-high speed until soft peaks form—the cream should hold its shape when the beaters are lifted but still have a gentle curl.
09 - Slice each cooled shortcake in half horizontally. Place the bottom half in a serving dish. Spoon some macerated strawberries over the base, followed by a generous dollop of whipped cream. Replace the top half of the shortcake. Add another layer of strawberries and finish with more whipped cream. Serve immediately for the best texture.