Rice the cauliflower finely if using fresh and microwave for 4-5 minutes until soft.
Allow the cauliflower to cool slightly, then squeeze out excess moisture using a clean towel for crisp texture.
In a mixing bowl, combine riced cauliflower, egg, Parmesan cheese, mozzarella cheese, oregano, garlic powder, salt, and pepper; mix to form a dough-like mixture.
Preheat oven to 400°F (200°C) and line a baking tray with parchment paper.
Scoop small portions of the dough and shape into bite-sized rounds on the baking tray.
Bake the cauliflower bases for 12-15 minutes until lightly golden and set.
Remove from oven and spoon pizza sauce on each bite, then sprinkle shredded mozzarella and add optional toppings.
Return the tray to the oven and bake for another 5-8 minutes until cheese is melted and bubbly.
Let the bites cool slightly before serving warm.