Grease twelve 2-1/2-inch muffin cups; set aside. In a large bowl, combine flour, cornmeal, brown sugar, cream of tartar, baking soda, and salt.
In a medium bowl, combine egg, milk, and melted butter; add all at once to the flour mixture. Stir until just moistened.
Spoon batter into prepared muffin cups, filling each two-thirds full.
Bake in a 400 degree F oven about 20 minutes or until lightly brown. Serve warm. Makes 12 muffins.