1 3/4 c all-purpose flour
3/4 cup stone ground cornmeal (not coarse)
4 t baking powder
1 t baking soda
1 t salt
1/2 stick cold unsalted butter, cut into 1/2-inch cubes
6 oz extra-sharp cheddar, coarsely grated (about 1 1/2 c)
3 T finely grated Parmigiano-Reggiano
3 scallions, finely chopped
1 1/3 c well-shaken buttermilk
Put a rack in middle of oven and preheat oven to 450°F. Butter a large baking sheet.
Whisk together flour, cornmeal, baking powder, baking soda, and salt in a bowl. Blend in butter with your fingertips or a pastry blender until mixture resembles coarse meal. Stir in cheeses and scallions with a wooden spoon. Add buttermilk and stir until just combined.
Drop dough in 8 equal mounds about 2 inches apart on baking sheet. Bake until golden, about 15 minutes. Transfer to a rack and cool to warm, about 10 minutes.
If serving with Turkey Sloppy Joes, split in half, and serve sloppy joe mixture over biscuits.