Preheat your oven to 375°F (190°C).
Slice the yellow bell peppers in half vertically and remove the seeds and membranes.
In a large non-stick skillet over medium-high heat, brown the ground beef until no pink remains, breaking it up with a spatula.
Drain any excess fat from the skillet, then stir in the cooked brown rice, tomato sauce, sea salt, black pepper, garlic powder, onion powder, and dried oregano.
Place the pepper halves in a baking dish and fill each cavity generously with the beef and rice mixture.
Top each pepper with a sprinkle of parmesan cheese.
Pour a small amount of water into the bottom of the baking dish to create steam, then cover with foil.
Bake for 20 minutes covered, then remove the foil and bake for an additional 10 minutes until the peppers are soft and the cheese is golden.