Lightly spoon flour into dry measuring cups; level with a knife. Combine flour and next 4 ingredients in a large bowl; cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Stir in cheese.
Combine buttermilk and egg in a small bowl, stirring with a whisk. Add to flour mixture, stirring just until moist.
Turn dough out onto a lightly floured surface; knead lightly 5 times with floured hands. Pat dough into an 8-inch circle on a baking sheet coated with cooking spray. Cut dough into 8 wedges, cutting into, but not through, dough. Coat lightly with cooking spray.
Bake at 400° for 24 minutes or until lightly browned.