2 cups all-purpose flour
1 tablespoon baking powder
1/4 teaspoon baking soda
2 teaspoons granulated sugar
1 teaspoon salt
6 tablespoons cold, unsalted butter, cut into small pieces
3/4 cup cold buttermilk, plus additional for brushing
Preheat the oven to 450 degrees F.
In a large mixing bowl, whisk together the flour, baking powder, baking soda, sugar and salt.
Cut in the butter, either using a pastry cutter or two knives or in a food processor, until the butter is in clumps the size of peas.
Add the buttermilk and work the dough just until it comes together in a ball.
Transfer the dough to a lightly floured board and knead it gently a few times before patting it into a rectangle.
Fold it in thirds like a letter, flatten it out into a 1/2-inch-thick rectangle again, and repeat folding and flattening once or twice more. Finish by patting it to 1/2-inch thick.
Using a 2-1/2-inch round biscuit cutter, cut out 12 biscuits. Arrange the rounds on the baking sheet and brush a bit of buttermilk over the their tops.
Bake in the oven for about 15 minutes, until they are puffed and golden brown.
Remove from the oven and serve warm.