Preheat the oven to 425 degrees F (220 degrees C). Line a muffin tin with parchment paper squares.

Grate cauliflower into a microwave-safe bowl using a fine grater. Chop any remaining pieces too small to grate and add to the bowl.

Cook in the microwave until cauliflower is soft and tender, 4 to 6 minutes. Pour into a clean dish towel and let cool enough to handle, 15 to 20 minutes.

Wrap the towel around cauliflower and squeeze out as much liquid as possible; the drier, the better.

Combine squeezed cauliflower, 1 cup mozzarella cheese, Parmesan cheese, egg, salt, pepper, garlic powder, and onion powder in a large bowl until well combined. Scoop evenly into the prepared muffin cups. Pat down cauliflower mixture with the back of a spoon, making it compact.

Bake in the preheated oven until crust is golden brown, about 15 minutes. Remove from the oven and spoon pizza sauce evenly onto each crust. Top with remaining 1 1/2 cups mozzarella cheese.

Return to the oven and bake until cheese is melted and golden brown, about 15 minutes. Let pizza bites sit in the pan for 5 minutes before removing to a wire rack to cool for 10 minutes. Remove parchment paper from the bottoms and arrange bites on a platter.