Preheat your oven to 375°F.

Cut the tops off the bell peppers and remove seeds and membranes. Place the peppers upright in a baking dish.

In a skillet over medium heat, cook the ground beef until browned, breaking it apart as it cooks.

Add the diced onion and garlic to the pan and sauté until soft and fragrant.

Sprinkle the taco seasoning over the beef mixture and stir until evenly coated.

Stir in the cooked rice (or cauliflower rice) and diced tomatoes, mixing thoroughly. Season with salt and pepper to taste.

Spoon the beef mixture into each pepper, packing it gently.

Top each stuffed pepper with shredded cheese.

Cover the baking dish with foil and bake for 25–30 minutes, until the peppers are tender.

Remove the foil and bake an additional 5–10 minutes, until cheese is melted and lightly browned.

Serve warm with your choice of optional toppings.