Macerate the Strawberries: In a medium mixing bowl, toss the sliced strawberries with the granulated sugar and fresh lemon juice. Let them sit at room temperature for at least 30 minutes while you prepare the biscuits. This draws out the natural juices to create a sweet syrup.

Preheat and Prep: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper.

Mix the Dry Ingredients: In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and salt.

Cut in the Butter: Add the very cold, cubed butter to the flour mixture. Using a pastry blender or your fingers, quickly cut or rub the butter into the flour until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining.

Form the Dough: Pour in the cold heavy cream. Use a fork or a wooden spoon to stir the mixture just until a shaggy dough begins to form. Do not overmix.

Bake the Biscuits: Drop the dough into 6 equal mounds onto your prepared baking sheet (they should look rustic). Brush the tops lightly with the egg wash and sprinkle generously with coarse sugar. Bake for 15 to 18 minutes, or until the shortcakes are puffed and deep golden brown. Let them cool slightly on a wire rack.

Whip the Cream: While the biscuits are cooling, pour the cold heavy whipping cream, powdered sugar, and vanilla extract into a chilled mixing bowl. Beat on medium-high speed until soft, billowy peaks form.

Assemble and Serve: Slice the warm biscuits in half horizontally. Spoon a generous amount of the juicy strawberries and their syrup over the bottom half of each biscuit. Add a large dollop of the freshly whipped cream, then place the top half of the biscuit over the cream. Serve immediately.