Wash bell peppers, slice off tops, and remove seeds.

In a skillet over medium heat, brown the ground meat with chopped onion. Drain fat if needed. Stir in diced tomatoes, cooked rice, minced garlic, Italian seasoning, salt, and pepper until heated through.

Fill each bell pepper generously with the meat mixture.

Place stuffed peppers upright in the slow cooker.

Pour enough broth or water to cover the bottom of the slow cooker (about half an inch).

Cover and cook on low for 6 hours or high for 3 hours.