01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together flour, sugar, baking powder, and salt until well combined.
03 - Add cold butter cubes to the flour mixture. Use a pastry cutter or fingertips to blend until mixture resembles coarse crumbs with pea-sized butter pieces remaining.
04 - Pour in cold milk and stir gently with a spatula just until dough comes together. Do not overmix or biscuits will become tough.
05 - Turn dough onto lightly floured surface. Gently pat into a 1-inch thick rectangle. Cut into 6 rounds using a 2.5-inch biscuit cutter, pressing straight down without twisting. Gather scraps and reshape to cut remaining biscuits.
06 - Place biscuits on prepared baking sheet. Brush tops lightly with beaten egg. Bake for 15–18 minutes until golden brown and cooked through. Transfer to wire rack to cool completely.
07 - Combine sliced strawberries, sugar, and lemon juice in a bowl. Let sit at room temperature for at least 20 minutes, stirring occasionally, until strawberries release their juices and become syrupy.
08 - Beat cold heavy cream, powdered sugar, and vanilla extract with an electric mixer or whisk until soft peaks form. Do not overbeat or cream will become grainy.
09 - Split cooled biscuits horizontally in half. Place bottom halves on serving plates. Spoon macerated strawberries and juices generously over biscuits. Top with dollops of whipped cream, then cover with biscuit tops. Serve immediately while biscuits are still fresh.