Brown the ground beef in a skillet on the stove top. Drain.
Add the beef, cut up bell pepper tops, rice, 1 cup of the marinara sauce, onion, salt, garlic powder, thyme and oregano to a medium sized bowl. Stir.
Stuff the peppers with the filling you just made. If there is any leftover filling add it to the bottom of the slow cooker.
Add remaining marinara sauce to the slow cooker.
Add the stuffed peppers in the slow cooker. I try not to let them rest on the sides of the slow cooker, but most of the time they end up falling over later.
Cover and cook on LOW for 5 hours without opening the lid during the cooking time.
Video
Notes
Can I add cheese to this?
Stuffed peppers often have cheese on top, though adding cheese is optional.
If you want a cheese fix, add about 2 tablespoons of shredded mozzarella cheese to each pepper 10 minutes before the cooking time is up.
Can a different type of meat be used?
Ground turkey
Ground chicken
Ground Italian sausage
Can I make this vegan?
Use soy crumbles instead of beef
Or a can of pinto beans
Or add extra veggies such as chopped squash or asparagus to the rice mixture.