Wash hands with soap and water.
Preheat oven to 375°F.
Gently rub celery, green pepper and tomato under cold running water.
Scrub onion and garlic with a clean vegetable brush under running water.
Chop onion, green pepper, celery and tomato. Mince garlic in a food processor.
Heat butter over medium heat in a large skillet. Add the onions, green peppers, celery and garlic to the skillet and sauté until crisp-tender.
Transfer to a very large bowl and stir in the remaining ingredients.
Place mixture into a greased casserole dish and tightly cover with aluminum foil.
Place the casserole dish on the center rack of the preheated oven and bake for 40 minutes. Stir the casserole twice during the 40-minute cooking process. Continue baking until the rice is tender and the internal temperature reaches 145°F on a food thermometer.
Serve warm and enjoy!