Preheat oven to 450 degrees F.
Whisk together flour, baking powder, sugar, baking soda, and salt in a bowl, then blend in butter with your fingertips until mixture resembles coarse meal. Stir in Cheddar and scallions. Add buttermilk and stir until just combined.
Drop dough in 12 equal mounds about 2 inches apart onto a buttered large baking sheet. Bake in middle of oven until golden, 18 to 20 minutes.
Recipe courtesy of Gourmet Magazine