Preheat your oven to 450°F (230°C) and line a baking sheet with parchment paper or lightly grease it.

1. In a large mixing bowl, whisk together the flour, baking powder, salt, baking soda, and sugar (if using).
2. Cut the cold butter into the flour mixture until it resembles coarse crumbs with pea-sized pieces of butter. Use a pastry cutter, fork, or your fingers.
3. Pour in the buttermilk and stir gently until the dough just comes together. Be careful not to overmix.
4. Turn the dough out onto a lightly floured surface. Gently knead the dough 3-4 times until it comes together, then pat it into a 1-inch thick rectangle.
5. Use a round biscuit cutter to cut out biscuits, pressing straight down without twisting. Place them on the prepared baking sheet, close together for soft sides or spaced apart for crispy edges.
6. Bake for 12-15 minutes, or until the biscuits are golden brown and cooked through.
7. Cool for a few minutes, then serve with butter, jam, or gravy.