Preheat oven to 400 degrees F (200 degrees C). Grease a pizza pan and dust with cornstarch.
Mix Cheddar cheese, gluten-free flour, egg, and melted butter in a large bowl until well combined. Season with Italian seasoning, garlic powder, and lemon pepper. Add water, 1 tablespoon at a time, until dough is formed.
Spread dough over the prepared pizza pan. Sprinkle with red pepper flakes.
Bake in the preheated oven until light golden brown, about 6 minutes.