Hull the strawberries and slice them lengthwise into thirds. Combine them with the sugar in a bowl, mixing thoroughly until the berries release some of their juices. Set the mixture aside to macerate.

Preheat your oven to 425°F (220°C) if using a conventional oven. For convection ovens with a fan, refer to note 2. Prepare a baking tray by lining it with parchment paper.

In a large mixing bowl, sift together the flour, cornstarch, baking powder, baking soda, salt, and sugar. Use a whisk to blend the dry ingredients uniformly.

Add the cubed, cold butter to the flour mixture. Using your fingertips, rub the butter into the dry ingredients until it forms a crumbly texture with visible small butter pieces throughout. The mixture should develop a light yellow hue.

Gradually pour in the buttermilk, gently stirring with a fork to combine. The mixture should resemble a coarse, shaggy dough. Avoid overmixing to preserve the desired biscuit texture.

Transfer the dough onto a floured surface and gently bring it together, forming a rectangular shape about ¾ inch thick. Take care not to overwork the dough.

Dip the edge of a 2½-inch cookie cutter or a thin-lipped glass in flour. Press straight down into the dough without twisting to cut out biscuits. Recombine scraps of dough to cut additional biscuits. This recipe yields approximately seven biscuits (refer to note 4 for an alternative cutting method).

Arrange the biscuits on the prepared tray, spacing them about ½ inch apart. Sprinkle the tops with sugar for added crunch. If the dough has warmed, chill it in the freezer for 10 minutes before baking. Bake for about 15 minutes, or until the tops are golden brown.

Let the biscuits cool on the tray for 20 minutes before assembling. While they cool, prepare the whipped cream.

In a mixing bowl, combine the heavy cream, sugar, and vanilla extract (if using). Using a hand mixer or stand mixer on medium speed, whip the cream until medium-stiff peaks form. Take care not to overwhip.

Carefully slice a biscuit in half with a serrated knife. Place the bottom half on a serving plate and generously layer it with the macerated strawberries and their juices. Top with a dollop of whipped cream.

Place the top half of the biscuit over the whipped cream. Garnish with additional whipped cream and a drizzle of strawberries with their syrup.

Serve immediately for the best experience (see note 5 for storage and freezing details).