Preheat the oven to 425°F (220°C)
Line a baking sheet or pizza pan with parchment paper
Cut cauliflower into florets
Pulse florets in a food processor until rice-sized
Microwave or steam the cauliflower rice until tender
Let the cauliflower cool slightly
Place the cooked cauliflower rice in a clean kitchen towel or cheesecloth
Squeeze out as much moisture as possible
Transfer the dry cauliflower to a bowl
Add egg
Add shredded mozzarella cheese
Add grated Parmesan cheese
Add salt
Add Italian seasoning or garlic powder, if desired
Mix until combined
Spread the mixture onto the prepared pan
Shape into a thin, even crust
Bake for 20 to 25 minutes
Remove from the oven
Add desired toppings
Bake again until toppings are cooked and cheese is melted
Slice and serve