Preheat oven to 350 degrees and grease 9 x 14 baking dish.
Brown beef in a large skillet over medium high heat for 5-6 minutes, or until cooked through. Season with salt and pepper. Drain excess grease and set aside.
Add ghee to same skillet, and add onion, garlic, sweet potato, carrots, and green bell pepper. Cook for 8-10 minutes, stirring frequently until sweet potatoes and carrots are fork tender.
Add diced tomatoes, tomato paste, and spices to pan; stir to combine. Add beef back to pan, toss to combine, and let simmer for 5-10 minutes.
Fill each pepper half with beef mixture and transfer to greased pan. Sprinkle all stuffed pepper halves with cheese, and bake for 20-25 minutes, until peppers are tender and cheese is slightly golden. Option to broil for remaining 1-2 minutes.