Preheat the oven to 450° F.Stand the cauliflower on its stem, cut them in to 1½ inch slices. Place on a baking sheet and rub with olive oil. In a bowl, combine the thyme, oregano, paprika, garlic, and onion powder. Sprinkle over the cauliflower, then season with salt and pepper. Bake 15 minutes. Remove from the oven and spoon over the marinara sauce. Top with equal amounts of the cheeses and then the pepperoni. Bake 5 minutes, then switch the oven to broil and broil 1-2 minutes, until the cheese is melted. Top with fresh basil. Enjoy!