You can consider adding spices such as cayenne/red chili powder. You can also add chopped green chilies or jalapenos. Add black beans and roasted bell peppers, chopped tomatoes, spices such as cumin powder, etc., to a Mexican/southern-style casserole. You can make the casserole crunchy by topping it with crushed cornflakes, Nachos, Tortilla Chips, or panko/regular bread crumbs. Make sure to generously drizzle melted butter to keep the topping crispy and flavorful.