For the Strawberries: In a large bowl, combine diced strawberries, granulated sugar, and lemon juice and stir until well combined. Cover bowl, transfer to refrigerator, and let macerate, stirring periodically, for at least 1 hour and up to 8 hours.

Meanwhile, for the Shortcakes: Using a fine-mesh strainer, sift flour into a large bowl, then add sugar, baking powder, and salt. Whisk for 30 seconds to combine. Add butter and, using your fingertips, press the butter into the dry ingredients until mixture resembles coarse bread crumbs with some pea-sized pieces of butter remaining.

In a measuring cup, stir together heavy cream and vanilla extract. Form a well in the center of the flour mixture, then pour cream into the well. Using a wooden spoon, stir until a shaggy dough forms, about 30 seconds (you might still see some crumbly flour bits in the bottom of the bowl, that's okay).

Turn dough and any unincorporated flour out onto a lightly floured work surface. Using your hands, pat dough into a mound; this should only take 10-15 seconds as the goal is not to knead, but to gently bring the dough together. Gently pat dough into a rectangle approximately 5- by 7.5-inches in size and about 1 inch thick.

Using a 2.5-inch round biscuit cutter, punch out dough into circles; for the cleanest cuts, try to press directly down instead of twisting the cutter and periodically wipe the cutter clean with a dry towel. Using a floured metal spatula, transfer dough circles to a parchment-lined rimmed baking sheet, allowing 2-3 inches between the cakes. Bring dough scraps together with your hands and repeat the process. Transfer baking sheet to the refrigerator and chill for 30 minutes.

While shortcakes chill, preheat oven to 400°F (205°C). Once chilled, use a pastry brush to brush tops of cakes with cold heavy cream, then sprinkle lightly with Demerara sugar. Bake until shortcakes are slightly risen, golden brown, and slightly cracked on top, 15 to 18 minutes. Allow shortcakes to cool on baking sheet for 5 minutes, then transfer to a wire rack and allow to cool until slightly warm while you prepare the whipped cream.

For the Whipped Cream: To a large metal mixing bowl or the bowl of a stand mixer fitted with the whisk attachment, add cold heavy cream and whip on medium-high speed until soft peaks form, about 4 minutes. Use a fine-mesh strainer to sift in confectioners' sugar, then add vanilla extract. Whip on high speed until just combined, about 10-15 seconds.

To Assemble: Using a serrated knife, slice each shortcake in half horizontally. Place bottom halves on dessert plates. Top each with a spoonful of macerated strawberries and a dollop of whipped cream, followed by the top half of the shortcake. Top with another spoonful of berries and another dollop of whipped cream.

If desired, dust with confectioners' sugar and/or sprinkle with extra Demerara sugar (for more crunch), and garnish with fresh herbs and/or whole strawberries. Serve immediately.