01 - Preheat oven to 400°F. Line a baking sheet with parchment paper and set aside.
02 - In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and salt until evenly combined.
03 - Add the cold cubed butter to the dry mixture. Using a pastry blender or your fingertips, cut the butter into the flour until the mixture resembles coarse crumbs with pea-sized pieces remaining.
04 - In a small bowl, whisk together the whole milk and egg until smooth. Pour the wet mixture into the dry ingredients and stir gently just until the dough comes together. Avoid overmixing.
05 - Drop rounded spoonfuls of dough onto the prepared baking sheet, yielding about 6 to 8 shortcakes. Bake for 15 to 18 minutes until the tops are golden brown. Transfer to a wire rack and cool completely, then break into bite-sized pieces.
06 - While the shortcakes bake, combine the diced strawberries, granulated sugar, and lemon juice in a bowl. Toss gently and let sit for 15 to 20 minutes until the strawberries release their natural juices.
07 - Place a mixing bowl and beaters in the freezer for 5 minutes. Pour in the heavy whipping cream, powdered sugar, and vanilla extract. Beat on medium-high speed until soft peaks form. Do not overwhip.
08 - In individual serving glasses or jars, layer shortcake pieces, macerated strawberries with their juices, and whipped cream. Repeat to create a second layer. Finish each trifle with a dollop of whipped cream and a few strawberry slices on top.
09 - Serve immediately, or cover and refrigerate for up to 2 hours before serving to allow the flavors to meld.