Ingredients
2 cups all-purpose flour
2 tsp baking powder
1 tsp salt
¼ tsp baking soda
7 Tbsp unsalted butter, chilled in freezer and cut into thin slices
¾ cup cold buttermilk
2 Tbsp buttermilk for brushing
Directions
Preheat oven to 425°.
Line a baking sheet with a silicone baking mat or parchment paper.
Whisk flour, baking powder, salt, and baking soda together in a large bowl. Cut butter into flour mixture with a pastry blender until the mixture resembles coarse crumbs, about 5 minutes. Make a well in the center of butter and flour mixture. Pour in buttermilk, stir until just combined.
Turn dough onto a floured work surface, pat together into a rectangle. Fold the rectangle in thirds. Turn dough a half turn, gather any crumbs, and flatten back into a rectangle. Repeat twice more, folding and pressing dough a total of three times.
Roll dough on a floured surface to about ½-inch thick. Cut out 12 biscuits using a 2½-inch round biscuit cutter.
Transfer biscuits to the prepared baking sheet. Lightly press an indentation into the top of each biscuit with your thumb; this helps biscuits rise evenly. Brush the tops of biscuits with 2 tablespoons buttermilk.
Transfer to a preheated oven and bake until golden brown, about 15 minutes.
Note: Grate a frozen stick of butter over the large holes of a cheese grater for a more even butter distribution. It is also much faster than using a pastry cutter.