Preheat oven to 425 degrees. Spread cauliflower in a single layer on baking sheet, drizzle with olive oil and Italian seasonings(garlic, oregano, basil, salt, pepper).
Roast cauliflower until golden brown @15-20 minutes.
Spray a large casserole dish with cooking spray and layer the roasted cauliflower at the bottom. Top with marinara sauce, mozzarella cheese and toppings of your choice. Bake in oven until cheese is melted about 5-10 minutes. Let cool 5 min and garnish with fresh oregano or basil.