Make the beef mince: Add the onion and garlic to a pan. Sauté for six minutes. Add beef mince, green bell pepper, and sweet corn. Add spices and oyster sauce. Cook for eight minutes.
Prepare ingredients: Slice sun-dried tomatoes and slice black olives. Grate mozzarella cheese and cheddar cheese.
Make the sandwich: Preheat the pan and butter the sliced bread on one side. Place the buttered side directly on the grill pan. Add the filling on the butter-free side. Add sliced olives, sun-dried tomatoes, and the grated cheeses. Cover and toast for four minutes on each side on low heat or until the cheese has melted.