1. Saute onion, celery, pepper, and garlic in oil. Add chili powder and cumin. When fragrant, add tomatoes, salt, oregano, and pepper. When tomatoes are cooked thoroughly, stir in the rice.
2. Top with the grated cheese and bake long enough to melt the cheese.
Tip: Replace green pepper with red or green chili peppers. Usually, large peppers contain less spice than smaller peppers and chilis.