Prepare the Fresh Strawberry Topping as directed in its respective recipe. Cover and set aside to thicken. Serve at room temperature or chilled.
In a large mixing bowl, combine the flour, baking powder, salt, and granulated sugar. Whisk to ensure even distribution of ingredients.
Incorporate the cubed cold butter into the flour mixture. Using a pastry cutter, blend the butter into the dry ingredients until the texture resembles coarse crumbs, with butter pieces about the size of a pea.
In a separate bowl, whisk together the cold buttermilk and egg. Gradually pour this mixture into the dry ingredients, stirring with a rubber spatula until a shaggy dough begins to form.
Lightly flour your hands and knead the dough briefly within the bowl, pressing in any remaining dry flour. If the mixture appears too dry, incorporate an additional tablespoon of cold buttermilk or ice water as needed.
Transfer the dough to a floured surface. Roll it out into an approximate 9x13-inch rectangle. Fold the dough in half, then in quarters, repeating once more to develop layers. Gently pat and roll the dough into a thickness of about 1 and 1/4 inches.
Dip a 2.5-inch biscuit cutter in flour and use it to cut out the shortcakes. Press straight down without twisting to ensure optimal rise. Re-roll any scraps as needed.
Arrange the shortcakes in a buttered cast-iron skillet or a greased 9x9-inch baking dish. Position them snugly, with either slight contact or about 1/2 inch apart, to encourage upward rise during baking.
If time allows, freeze the pan of shaped shortcakes for 20 minutes. This step enhances the formation of flaky layers when baked. Meanwhile, preheat the oven to 425°F.
Before baking, brush the tops of the shortcakes with buttermilk or heavy cream for a golden finish. Sprinkle with sugar for a crisp texture.
Bake at 425°F for approximately 18-22 minutes, or until the tops develop a deep golden hue and the edges are firm. Check for doneness by gently splitting one open—if the interior appears undercooked, return them to the oven. If browning too quickly, tent with foil for the final minutes.
While the shortcakes bake, prepare the whipped cream by beating the heavy cream, powdered sugar, and vanilla in a large bowl using a stand or hand mixer. Whip on high speed for 2-5 minutes until peaks form and hold their shape. Refrigerate until ready to serve.
Once baked, assemble the shortcakes while warm. Slice each in half, layering the bottom with strawberry topping and whipped cream. Replace the top half and garnish with additional strawberries and whipped cream.
Make-Ahead Instructions
To prepare in advance, shape the shortcakes and freeze them unbaked for up to two months. When ready to bake, place them directly from the freezer into a preheated oven—bake at 450°F for 5 minutes, then reduce to 400°F and continue baking for 15 minutes.