Mozzarella Cheese, optionalOMIT FOR WHOLE30! Use Dairy Free If Needed, optional.
Preheat oven to 350 degrees
Cut the tops off of the bell peppers and take out the seeds. Place cut side down on a large baking sheet and bake for 10 minutes.
Heat the oil over medium heat in a large skillet.
Once hot, add the onion and ground beef and cook until browned. Drain off fat if desired.
Then, add the mushroom, garlic, and zucchini. Saute until veggies are tender, 5 - 8 minutes.
Season with salt and pepper.
Stir in 1 Cup of marinara sauce and mix to combine. Taste and add more salt and pepper if needed.
Arrange bell peppers in a medium-sized baking dish and spoon the filling into each bell pepper. Spoon additional marinara sauce over each bell pepper to keep them from drying out. Then, lightly sprinkle with dairy-free mozzarella cheese if desired.