Preheat your oven to 400°F (204°C) and line a half-sheet baking pan with parchment paper.

In a large bowl, whisk together the all-purpose flour, kosher salt, baking powder, baking soda, and granulated sugar.

Grate the frozen unsalted butter into the dry mixture and toss until evenly distributed.

In a separate bowl, whisk together the buttermilk and sourdough discard, then pour into the dry ingredients and fold until clumps form.

On a floured surface, pat the dough into a rectangle about ¾-inch thick and perform three or four folds, then pat it down again.

Cut the dough into rounds or squares and place on the prepared baking sheet, leaving space between.

Chill the shortcakes for at least 30 minutes.

After chilling, brush the tops with buttermilk and sprinkle with raw sugar before baking for about 20 minutes.

While baking, combine sliced strawberries with sugar, lemon zest, and vanilla extract; let sit for 30 minutes.

Whip heavy cream with sugar and a pinch of salt until stiff peaks form.

Once baked, split the biscuits, layer with strawberries and whipped cream, then top with the other half.

Serve immediately for the best texture.