Line a rimmed pizza pan or baking sheet with parchment paper, and preheat the oven to 425ºF.
Place the cauliflower in a microwave-safe bowl and add a splash of water. Cover. Microwave for 3 minutes or until tender. Allow to cool.
2½ cups cauliflower florets
Place cauliflower in a high powered blender or food processor and pulse until fully chopped and in tiny pieces. It will almost be grated.
Remove as much water as possible from the processed cauliflower by using paper towels or by placing the cauliflower in a cheesecloth or thin linen cloth and squeezing out as much water as you possibly can. This step is important for a firm crust.
Add the egg, 1¼ cups mozzarella cheese, Parmesan cheese, garlic salt, pepper, red pepper flakes, and basil. Stir to combine all of the ingredients.
1 large egg, 1½ cups freshly shredded mozzarella cheese, 2 tablespoons freshly grated Parmesan cheese, 1 teaspoon garlic salt, ½ teaspoon ground black pepper, ¼ teaspoon crushed red pepper flakes, 1 tablespoon chopped fresh basil leaves
Pour the cauliflower mixture onto the pizza pan or baking sheet and form the shape of crust you want. Pat down to create a flat surface.
Press a paper towel on the top of the crust to absorb some more moisture, then throw the paper towel away.
Lightly spray with cooking spray, then bake for 15-20 minutes or until golden and firm to the touch, flipping the crust over after 10 minutes.
Spoon on the tomato sauce, followed by remaining mozzarella, cheddar, leeks, mushrooms, and pepperonis. (Feel free to use any toppings that you love instead)
1½ cups freshly shredded mozzarella cheese, ¼ cup tomato sauce, ¾ cup freshly shredded sharp cheddar cheese, 8 pepperoni slices, ¼ cup chopped cremini mushrooms, 1 tablespoon chopped leeks
Bake for another 5-10 minutes until melty. Allow to cool slightly. Slice and serve. Enjoy!