Sage Buttermilk Biscuits with Sausage and Cheddar

Preheat oven to 450 °F. Whisk together flour, sage, baking powder, sugar, baking soda, and salt. Blend in butter with your fingers or a pastry blender until mixture resembles coarse meal. Stir in grated cheese, then buttermilk, stirring until a dough forms. Gather dough into a ball and gently knead on a lightly floured surface 8 times. Pat dough into an 8- by 4-inch rectangle and cut into 8 (2-inch) squares. Arrange squares about 1 inch apart on a greased baking sheet and brush tops with additional buttermilk. Bake in middle of oven until golden brown and biscuits are cooked through, about 15 minutes. Leave oven on. Transfer biscuits to a rack to cool 10 minutes.