Heat the oven: Heat the oven to 400°F (200°C) with a baking sheet or pizza stone inside.
Assemble the pizza: Lay the keto frozen pizza crust out and spread the sugar-free pizza sauce over the top.
Top with toppings: In this order layer mozzarella cheese, pepperoni, mushrooms, bell pepper and sprinkle with Italian seasoning.
Bake: Transfer the pizza to the prepared hot baking sheet and bake for 15 – 20 minutes or until the cheese is golden and bubbly.
Rest and serve: Let the pizza rest for 5 minutes before slicing and serving.