In a medium bowl, add the strawberries, sugar, and vanilla extract. Stir to coat the strawberries and let the mixture sit at room temperature for 2 hours.
In a large bowl, using an electric mixer on medium-low speed, whip the heavy cream until it reaches soft peaks. Cover and refrigerate.
Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper and set aside.
In a medium bowl, whisk together the eggs, sour cream, and vanilla.
In a large bowl, combine flour, sugar, baking powder and salt. Using the large side of a grater, grate the frozen butter directly into the dry ingredients. Stir to coat in the flour mix.
Add your wet ingredients into the dry and stir until combined. Do not overmix as this will make the shortcakes tough.
On a floured surface gently press down your dough to 1 inch thick. With a round 3 inch cutter cut out your shortcakes.
Transfer the shortcakes to your prepared baking sheet and, using a pastry brush, glaze the tops with egg wash.
Bake for 18-20 minutes or until golden brown. Remove from the oven and allow to cool completely on a wire rack.
Split the shortcakes in half horizontally. Spoon about ½ cup of the macerated strawberries with their juices onto each shortcake bottom. Top with a generous spoonful of chilled whipped cream, and cover with the tops. Dust the shortcakes with icing sugar.
