Preheat your oven to 375°F.
Slice the tops off the bell peppers and carefully remove the seeds and white membranes from the inside.
Heat the olive oil in a large skillet over medium-high heat and add the ground beef.
Cook the beef until fully browned, using a spatula to break it into small crumbles.
Stir in the cooked brown rice, tomato puree, sea salt, black pepper, garlic powder, and onion powder.
Lower the heat and simmer the beef mixture for 3-5 minutes until the flavors are well combined.
Stand the hollowed peppers upright in a baking dish and fill each one to the top with the beef and rice mixture.
Cover the baking dish tightly with foil and bake for 25 minutes.
Remove the foil and continue baking for another 10 minutes until the peppers are tender and slightly charred on the edges.
Garnish with freshly chopped parsley and serve warm.