01 -
Put the cauliflower pieces in a bowl safe for the microwave. Add 1 cup of water, cover it with a wet paper towel, and microwave for 3 minutes on high heat until it's tender but not too soft. Drain the water, pat it dry with a paper towel, and set it aside for later.
02 -
Heat your oven to 400°F (200°C).
03 -
Drop the Italian sausage into a big pan on medium-high. Cook it for around 15 minutes, then drain the fat. Keep it aside.
04 -
Throw some olive oil into the same skillet and sauté the mushrooms on medium-high. Let them cook for 10 minutes to release the water. Set them to the side when finished.
05 -
Lightly spray a 13x9 dish with non-stick spray. Spread ½ cup of marinara at the bottom.
06 -
Combine the cooked sausage, mushrooms, green peppers, and cauliflower in a big mixing bowl. Toss it around until it's evenly combined.
07 -
Put half the mix from your bowl into the casserole pan first. Add ½ cup of the marinara on top, then half of the pepperoni. Gently press them under the mix before sprinkling 6 ounces of mozzarella on top.
08 -
Top with the last half of the bowl mixture. Layer on the remaining marinara, the other half of the pepperoni slices (keep 10 pieces aside for later), and the rest of the shredded mozzarella.
09 -
Mix the Parmesan and herbs in a tiny bowl. Sprinkle it over the top of the casserole, then arrange your 10 leftover pepperoni slices as a finishing touch. Pop the casserole into the preheated oven for 30 minutes, or until the cheese is melted and everything is heated all the way through.