Prepare corn muffin mix according to package directions. Spread in a well-greased 10-inch flan dish or a 9x1-1/2-inch round baking pan.
Bake the corn muffin mixture in a 400 degree F oven for 10 to 12 minutes or until wooden toothpick inserted comes out clean. Cool in the pan on a wire rack for 5 to 10 minutes.
Meanwhile, in a large skillet, cook meat and onion until meat is browned; drain if necessary. Stir in water and seasoning mix; bring to boiling. Reduce heat; simmer, uncovered, for 5 minutes.
Loosen edges of cornbread and carefully unmold onto an ovenproof platter. Spoon meat atop. Sprinkle with cheese. Bake, uncovered, 5 minutes.
If you like, top with onion, lettuce, olives, sour cream, guacamole, peppers, and/or tomato. Makes 6 servings.