Preheat your oven to 400 degrees and grease a 9x9 baking dish.
Steam your cauliflower (I used a microwave) until fork tender and then add to a blender or food processor. Add in the nutritional yeast, salt, pepper, garlic powder, onion powder, oregano, and egg and blend until smooth.
Add your ground pork sausage, diced onion, garlic, and 3/4 of the green pepper into a pan over medium high heat and cook until browned. Once browned, chop up all but 6 pieces of pepperoni into small bites and mix in with the tomato sauce.
Pour the meat mixture into your greased baking dish and spread out the cauliflower mixture evenly overtop. Top it all off with your remaining 6 slices of pepperoni, sliced mushrooms, green peppers, and sliced olives.
Place into the oven and bake for 25-30 minutes or until the toppings have toasted up slightly. Top with red pepper flakes to taste before serving.
* This recipe will cut WAY more easily if you allow it to come to room temperature and cool it in the fridge for a few hours before slicing. However, if you don't mind a messy plate, feel free to dig right in!