Step 1: Preheat your oven to 375°F (190°C). Lightly grease individual oven-safe bowls or a small baking dish.
Step 2: In a large skillet or pan, cook the ground beef or Italian sausage over medium-high heat, breaking it up with a spoon, until fully browned. If using leaner meat, add 1 tsp olive oil. Drain any excess fat.
Step 3: Add the minced garlic and chopped onion (if using) to the skillet with the cooked meat. Sauté for 2-3 minutes until the garlic is fragrant and the onion is softened.
Step 4: Stir in the low-carb marinara sauce, Italian seasoning, dried oregano, salt, and black pepper. Bring the mixture to a gentle simmer, then reduce heat to low and let it cook for 5-7 minutes, allowing the flavors to meld.
Step 5: Divide the meat and sauce mixture evenly among your prepared oven-safe bowls or baking dish.
Step 6: Sprinkle your chosen toppings (pepperoni, mushrooms, black olives, etc.) over the meat mixture in each bowl.
Step 7: Generously top each bowl with the shredded mozzarella, shredded provolone, and grated Parmesan cheese.
Step 8: Place the bowls on a baking sheet and bake in the preheated oven for 15-20 minutes, or until the cheese is melted, bubbly, and lightly golden brown. For an extra golden crust, you can broil for the last 1-2 minutes, watching carefully to prevent burning.
Step 9: Carefully remove the bowls from the oven. Let them cool for a few minutes before serving, as the cheese and sauce will be very hot. Garnish with fresh basil or red pepper flakes if desired, and serve immediately.