Preheat the oven to 425°F (220°C) and line a baking sheet with parchment paper.
In a large mixing bowl, whisk together the sifted flour, sugar, baking powder, and salt until well combined.
Add the cold, cubed butter to the flour mixture. Using a pastry cutter or forks, cut the butter into the dry ingredients until the mixture resembles coarse crumbs with small pea-sized bits remaining.
Pour in the buttermilk and vanilla extract, stirring gently just until the dough comes together. Be careful not to overmix; the dough should be slightly sticky.
Turn the dough onto a lightly floured surface and fold it gently a few times to bring it together. Pat it into a 1-inch thick rectangle.
Use a round cutter to cut out shortcakes and place them onto the prepared baking sheet, spacing them about 1 inch apart.
Bake for 12-15 minutes until the tops are golden brown and the shortcakes feel firm to the touch. Remove from oven and let cool slightly.
While the shortcakes cool, place sliced strawberries in a bowl and sprinkle with sugar. Toss gently and let sit for about 10 minutes to macerate, releasing their juices and developing a bright, fresh flavor.
In a separate bowl, whip the heavy cream with powdered sugar until soft peaks form and the cream is fluffy, with a light sweetness.
Cut the cooled shortcakes in half horizontally and layer the bottom half with a generous spoonful of strawberries and some of their juices.
Top the strawberries with a dollop of whipped cream and then place the top half of the shortcake over it.
Finish by spooning additional strawberries and whipped cream over the assembled shortcake for a luscious presentation. Serve immediately for the best flavor and texture.