01 - Preheat oven to 400°F. Grease a standard 12-cup muffin tin or line with paper liners, preparing 6 cups for use.
02 - In a large bowl, whisk together flour, sugar, baking powder, and salt until thoroughly combined.
03 - Cut in the cold butter using a pastry blender or your fingers until the mixture resembles coarse crumbs with small pea-sized butter pieces remaining.
04 - In a small bowl, whisk together milk, egg, and vanilla extract until fully incorporated.
05 - Pour the wet mixture into the flour mixture. Stir gently just until combined; the batter should be slightly lumpy. Do not overmix.
06 - Divide batter evenly among 6 prepared muffin cups. Bake for 16-18 minutes until golden brown and a toothpick inserted in the center comes out clean. Cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.
07 - While shortcakes bake, combine sliced strawberries, sugar, and lemon juice in a bowl. Stir well to coat and let sit for at least 20 minutes, stirring occasionally, until strawberries release their juices and become syrupy.
08 - In a chilled bowl, beat heavy cream, powdered sugar, and vanilla extract with a hand mixer or whisk until soft peaks form when the beaters are lifted.
09 - Slice each cooled shortcake cup in half horizontally. Place the bottom halves on serving plates. Spoon macerated strawberries and their juices generously over the bottoms, top with a generous layer of whipped cream, then cover with the top halves. Add additional strawberries and a final dollop of whipped cream on top. Serve immediately for best texture.