Cook in an electric frying pan. Heat fry pan at 300ºF. Add oil, beef, onion and garlic; cook until beef is browned, stirring occasionally. Drain excess fat. Stir in salsa, olives, oregano, cumin, salt and pepper; cook, covered, at 200ºF. for 5 minutes. Make corn muffin mix according to package directions, using eggs, milk and chili powder, fold in cheese. Spoon batter over beef mixture in fry pan; cook at 225ºF. with cover ajar 1 inch, until batter is cooked through, about 20 to 25 minutes. Serves 8.