Lightly spoon flour into dry measuring cups; level with a knife.
Combine flour, baking powder, sugar, salt, and pepper in a large bowl; cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Stir in cheese and ham.
Combine buttermilk and egg whites, stirring with a whisk.
Add to flour mixture, stirring just until moist.
Turn dough out onto a lightly floured surface; knead lightly 4 to 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.
Bake at 400 for 20 minutes or until lightly browned.