Preheat the oven: Preheat your oven to 375°F (190°C).

Prepare the bell peppers: Cut off the tops of the bell peppers and remove the seeds and membranes. Brush the insides of the peppers with olive oil and place them in a baking dish.

Cook the filling: In a large skillet, heat olive oil or butter over medium heat. Add the ground beef or lamb and cook until browned, about 5-7 minutes. Stir in the chopped onion and garlic, cooking for an additional 3-4 minutes until softened. Add the cauliflower rice and beef broth, cooking for another 5 minutes until the cauliflower rice is tender. Season with salt, pepper, fresh parsley, and thyme.

Stuff the peppers: Spoon the beef and cauliflower mixture into the prepared bell peppers. If desired, top each stuffed pepper with shredded cheddar cheese.

Bake: Cover the baking dish with foil and bake in the preheated oven for 25-30 minutes, or until the peppers are tender.

Serve: Garnish with additional fresh parsley and serve hot.