Stuffed Peppers without Rice

Name: Stuffed Peppers without Rice
Prep time: 10 min
Cook time: 10 min
Total time: 20 min
Cuisine: American
Ingredients: 3 bell peppers; 2 tablespoon olive oil; 1 medium yellow or white onion, diced; 3 garlic cloves, minced; 1 pounds ground beef ((you can use any meat you have available)); 2 cups riced cauliflower; 1 cup chunky marinara sauce ((sugar-free)); 1 teaspoon fresh thyme; ½ teaspoon sea salt; ¼ teaspoon freshly ground pepper; 1 cup mozzarella, shredded (divided); fresh herbs ((to garnish))