PREHEAT oven to 350°F. Grease an 8-inch square baking pan.
COMBINE flour, sugar, cornmeal, baking powder and salt in a medium bow. Combine milk, eggs, vegetable oil and melted butter in a small bowl; mix well. Add to flour mixture; stir just until blended. Pour into prepared baking pan.
BAKE for 35 minutes or until wooden pick inserted in center comes out clean.
SPOON batter into 18 to 20 greased or paper-lined muffin cups, filling 2/3 full. Bake for 18 to 20 minutes or until wooden pick inserted in center comes out clean. Cool in pans on wire racks for 5 minutes; remove to wire racks to cool slightly. Serve warm.