Preheat oven to 375°.
Lightly spoon flour into dry measuring cups; level with a knife. Combine flour, cornmeal, sugar, baking powder, and salt in a large bowl; cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Add milk and egg to cornmeal mixture; stir just until moist.
Turn dough out onto a lightly floured surface, and knead lightly 4 times with floured hands. Cover a baking sheet with parchment paper; coat with cooking spray. Pat dough into a 7-inch circle on prepared baking sheet. Cut dough into 8 wedges, cutting into but not through dough.
Bake at 375° for 22 minutes or until golden brown and a wooden pick inserted in center comes out clean. Serve warm.