01 - Preheat oven to 400°F. Grease a standard 12-cup muffin tin or line with paper liners, using 6 cups.
02 - In a large bowl, whisk together flour, sugar, baking powder, and salt until thoroughly combined.
03 - Cut in the cold butter with a pastry blender or your fingers until the mixture resembles coarse crumbs.
04 - In a small bowl, whisk together milk, egg, and vanilla extract. Pour into the flour mixture and stir just until combined. Do not overmix.
05 - Divide batter evenly into 6 muffin cups. Bake for 16-18 minutes, or until golden and a toothpick comes out clean. Cool in pan for 5 minutes, then transfer to a wire rack to cool completely.
06 - While shortcakes bake, combine sliced strawberries, sugar, and lemon juice in a bowl. Stir well and let macerate for at least 20 minutes to release natural juices.
07 - In a chilled bowl, beat heavy cream, powdered sugar, and vanilla with a hand mixer until soft peaks form.
08 - Slice each shortcake cup in half horizontally. Spoon strawberries and their juices onto the bottom halves, top with whipped cream, then replace the top halves. Add more strawberries and a dollop of whipped cream on top. Serve immediately.