Cut tops off peppers. Hollow out inside and discard seeds. Chop half the tops and set aside.
In skillet, saute garlic in olive oil until fragrant. Add in chopped green peppers from tops. Cook for about five minutes.
Add in ground beef and cook until browned.
Mix in diced tomatoes, Italian seasoning, sea salt, and onion powder. Cook another five minutes.
Stuff beef mixture into each hollowed out green pepper. Top each with 1 tablespoon marinara sauce then sprinkle with the chopped cheese.
Combine the remaining marinara sauce with any liquid remaining in the pan used to cook beef mixture. Pour into an 11x7 baking dish. Place stuffed peppers on top.
Bake at 375°F degrees for about 20 minutes.
If you want softer peppers, it's best to boil or blanch the peppers before stuffing and baking. About 10 minutes in boiling water is recommended. Otherwise, they will likely be a bit crunchy.You can also make this recipe in the slow cooker. Just cook the meat filled peppers without cheese in the crock pot for 4-5 hours on low. The cheese can be added at the end until melted, about 10 minutes more.