Preheat the oven to 400. Spray a large casserole dish with cooking spray.
Add the peppers to the baking dish. Cover with foil. Bake for 20 minutes.
Meanwhile, brown the meat in a large frying pan. Add the cauliflower rice and seasonings.
After the peppers have baked for 20 minutes remove the pan from the oven. Top the peppers with the cooked meat. Drizzle on the marinara sauce and sprinkle with the cheese.
Bake uncovered for 10 minutes or until the cheese melts.
Optional: Broil for 2-3 minutes to brown the cheese.