01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large mixing bowl, combine flour, sugar, baking powder, and salt. Add cubed butter and cut in with your fingers or a pastry blender until the mixture resembles coarse crumbs.
03 - Whisk together heavy cream and egg. Pour into the dry mixture and stir just until the dough comes together. Avoid overmixing.
04 - Turn dough onto a lightly floured surface and pat into a ¾-inch thick round. Cut into small squares or rounds, about 1 inch in size, suitable for individual trifle portions.
05 - Arrange shortcake pieces on the prepared baking sheet and bake for 12–15 minutes until golden brown. Transfer to a wire rack and cool completely.
06 - Toss sliced strawberries with granulated sugar and lemon juice in a bowl. Let stand for 15 minutes until the berries release their natural juices.
07 - Beat chilled heavy cream, powdered sugar, and vanilla extract on high speed using an electric mixer until stiff peaks form.
08 - Layer shortcake pieces, macerated strawberries with their juices, and whipped cream in individual serving glasses. Repeat the layers and finish with a dollop of whipped cream topped with fresh strawberry slices.
09 - Serve immediately, or refrigerate for up to 2 hours before serving.