- Preheat oven to 400F.
- Sauté bell pepper, onion, 1/2 tsp salt and 1/4 tsp pepper in butter for 3-5 minutes over medium heat in a large pan.
- Combine seasoning ingredients in a small bowl.
- Add ground beef and continue cooking for an additional 7-10 minutes.
- When meat is almost done cooking, drain liquid from pan and add seasoning ingredients. Continue cooking until meat is completely cooked through.
- Turn off heat and mix in 1 1/2 cups of the cheese.
- Line a rimmed baking sheet with aluminum foil and place zucchini boats on it (cut-side up).
- Drizzle a bit of olive oil and sprinkle salt on the inside of each boat, for seasoning.
- Scoop even amounts of meat mixture into the 8-10 zucchini boats.
- Cover boats with a sheet of aluminum foil and cook for 15 minutes.
- Remove aluminum foil and continue cooking an additional 10-15 minutes, or until zucchinis are completely cooked.
- Top each boat with about a tablespoon of cheese and return to oven for 1-2 more minutes to melt cheese. Serve with chopped onions.