Preheat your oven to 400°F (200°C).

Microwave cauliflower florets with a splash of water for 3 minutes until tender. Drain and pat dry.

In a skillet, brown the Italian sausage for about 15 minutes and drain excess grease.

Sauté mushrooms in the same skillet for about 10 minutes until tender.

Grease casserole dish and spread ½ cup of pasta sauce on the bottom.

Combine steamed cauliflower, cooked sausage, sautéed mushrooms, and chopped green peppers in a large bowl.

Layer half of the mixture in the casserole dish, top with ½ cup sauce, half of the pepperonis, and 6 oz of mozzarella cheese.

Repeat the layering with remaining mixture, sauce, pepperonis, and mozzarella.

Blend Parmesan cheese with Italian seasoning and sprinkle over the top.

Bake for about 30 minutes until cheese is melted and golden.

Allow to cool for 10-15 minutes before slicing and serving.