Preheat your oven to 375°F (190°C). Wash the bell peppers thoroughly. Carefully cut off the tops, then remove all seeds and membranes from inside each pepper.

If you desire a softer rice texture or wish to reduce baking time, you can pre-cook 1 cup of brown rice according to its package directions. Adjust diced tomatoes slightly if pre-cooking rice to avoid an overly wet filling.

In a large skillet, brown the ground beef over medium-high heat, breaking it up with a spoon as it cooks. Once cooked, drain off any excess grease.

Add the chopped yellow onion to the skillet with the browned ground beef and cook for 3-5 minutes until it softens and becomes translucent. Then, add the minced garlic and cook for another minute until fragrant.

Stir in the undrained diced tomatoes, tomato sauce, Italian seasoning, Worcestershire sauce, salt, and black pepper. If you are using pre-cooked brown rice, add it now. Bring the mixture to a simmer and cook for 5-10 minutes, stirring occasionally, allowing the flavors to meld. If using uncooked brown rice, ensure the mixture is saucy enough to cook the rice; add a splash of water or broth if needed.

Spoon the ground beef and rice filling into each prepared bell pepper, packing it firmly but not too tightly. Fill the peppers almost to the top, leaving a small space for expansion during baking.

Arrange the stuffed bell peppers upright in a baking dish. Pour about ½ cup of water or broth into the bottom of the dish to create steam and prevent drying. Cover the baking dish tightly with aluminum foil.

Bake in the preheated oven for 45-60 minutes, or until the bell peppers are tender when pierced with a fork and the brown rice is fully cooked through. Baking time may vary based on pepper size and whether rice was pre-cooked.

If you are using cheese, remove the foil during the last 10-15 minutes of baking. Sprinkle shredded cheese generously over the top of each stuffed pepper and continue to bake, uncovered, until the cheese is melted and bubbly.

Let the stuffed bell peppers rest for a few minutes before serving. Garnish with fresh chopped parsley, if desired, and serve hot.