Preheat oven to 400°.
Lightly spoon flour into dry measuring cups; level with a knife. Combine flour, cornmeal, baking powder, and salt in a medium bowl, stirring with a whisk. Cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Stir in corn and pepper. Add buttermilk, stirring just until moist (dough will be slightly sticky).
Turn dough out onto a lightly floured surface, and knead lightly 2 or 3 times with lightly floured hands. Pat the dough into a 9-inch circle on a baking sheet coated with cooking spray. Cut dough into 12 wedges, cutting to, but not through, dough. Bake at 400° for 25 minutes or until lightly browned. Cool on a wire rack.