Preheat the Oven: Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
Prepare the Crust: If using cauliflower, chop it into florets and steam or microwave it until soft. Then, pulse in a food processor until it forms rice-sized pieces. Squeeze out any excess water from the cauliflower using a clean towel. If using almond flour, skip this step. In a mixing bowl, combine the cauliflower (or almond flour), egg, Parmesan, mozzarella, garlic powder, onion powder, salt, and pepper. Mix until well combined.
Shape the Crust: Transfer the mixture to the prepared baking sheet and shape it into a thin circle or rectangle, about 1/4-inch thick. Bake for 10–12 minutes, or until the crust is golden and firm.
Add the Toppings: Remove the crust from the oven. Spread the tomato sauce evenly over the crust, then add mozzarella cheese, shredded chicken, bell peppers, mushrooms, and any other desired toppings.
Bake Again: Return the pizza to the oven and bake for another 8–10 minutes, or until the cheese is melted and bubbly. Remove from the oven and garnish with fresh basil, if desired.
Serve and Enjoy: Let the pizza cool for a few minutes before slicing and serving.