2 cups all-purpose flour
2 tsp. baking powder
1/2 tsp. baking soda
1/2 tsp. kosher salt
1/2 cup cold unsalted butter, diced into small cubes
1/2 tsp. cracked black pepper
1 cup shredded Parmesan cheese
1/4 cup finely chopped scallions
3/4 cup buttermilk
Preheat oven to 425°F.
Sift the flour, baking powder, baking soda, and salt into a medium bowl. Cut the cold butter into the flour mixture with a pastry cutter or fork. It should look like cornmeal with small lumps. Stir in the pepper, cheese, and scallions. Make a well in the center of the mixture and pour the buttermilk into it. Gently fold in the buttermilk until a dough forms.
Place the dough onto a lightly floured work surface. Gently knead the dough seven or eight times. Hand pat it out to a one-inch thickness. Use a 2½-inch biscuit cutter to cut the biscuits. Do not twist the cutter.
Reform the scraps and pat out again. Repeat the cutting process. Place the biscuits tightly together in a greased 12-inch cast-iron skillet or other baking pan. Bake for eight minutes. Turn the skillet back to front. Bake another eight to 10 minutes, or until the biscuits are golden brown. They’re best when served immediately.