Preheat your oven to 350°F. Slice the bell peppers in half lengthwise, removing the seeds and membranes. Arrange the peppers, cut side up, in a microwave-safe 13×9-inch dish. Add 2 tablespoons of water to the bottom of the dish and lightly cover with parchment paper. Microwave the peppers for around 3 minutes, just until they begin to soften. Drain any extra liquid from the dish.

While the peppers soften, heat 1 tablespoon of olive oil in a large skillet or Dutch oven over medium-high heat. Add the ground beef and diced onion, cooking until the beef is no longer pink. Drain any excess fat from the pan. Stir in the cooked rice, tomato sauce, Worcestershire sauce, Italian seasoning, sugar, garlic powder, onion powder, and a pinch of salt and pepper. Mix in ½ cup of shredded cheddar and ½ cup of shredded Monterey Jack or mozzarella. Taste the filling and adjust seasoning with additional salt and pepper if needed.

Season the interior of each pepper half with salt and pepper, then stuff them generously with the prepared beef and rice mixture. Drizzle the stuffed peppers with the remaining tablespoon of olive oil, cover the dish with foil, and bake for about 35 minutes, or until the peppers are tender and the filling is heated through.

Remove the foil, top each pepper with the remaining ½ cup of shredded cheddar and Monterey Jack or mozzarella cheese. Return the dish to the oven and bake, uncovered, for an additional 10 minutes or until the cheese is melted and bubbly. Serve the peppers warm, garnished with freshly chopped parsley or basil if desired.