Step 1: Prepare the Oven
Preheat your oven to 450°F. Line a baking sheet with parchment paper.

Step 2: Combine the Dry Ingredients
In a large mixing bowl, whisk together the flour, baking powder, baking soda, sugar, and kosher salt.

Step 3: Cut in the Cold Butter
Add the cold, cubed butter to the flour mixture. Use a pastry cutter to cut the butter into the flour until you have a coarse, crumbly mixture with small pieces of butter still visible. Don’t work the butter in completely. Those pieces are what help create flaky layers as the biscuits bake.

Step 4: Add the Cheese and Apples
Gently stir the shredded sharp cheddar and chopped apples into the flour mixture. Toss everything together until evenly distributed.

Step 5: Add the Buttermilk
Pour the cold buttermilk into the mixture. Gently stir until the dough just comes together. Avoid overmixing. The dough should be soft and slightly shaggy.

Step 6: Shape the Biscuit Dough
Turn the dough onto a lightly floured surface. Gently bring it together with your hands, then pat it into a thick rectangle.

Step 7: Create the Flaky Layers
Fold the dough in half, then gently pat it out again. Repeat this folding process a couple of times. Work quickly so the butter stays cold.

Step 8: Cut the Biscuits
Pat the dough to about ¾-inch to 1-inch thick. Cut out the biscuits using a biscuit cutter or a knife. Press straight down rather than twisting the cutter so the layers can rise properly.

Step 9: Arrange the Biscuits
Place the biscuits on the prepared baking sheet. They can be close together for softer sides or spaced farther apart for more golden edges.

Step 10: Bake the Biscuits
Bake at 450°F for roughly 15 minutes, or until the biscuits are puffed and golden brown on top.

Step 11: Serve Warm
Let the biscuits cool for a few minutes before serving. They are especially good while still warm, when the cheddar is soft and the layers are at their flakiest.