>>I flipped it so it would cook on both sides
>>
>
>i did put a pizza in once with the cardboard. there was no
>problem, the crust was maybe a bit undercooked. i thought
>there was no cardboard when i opened it. i didnt put it in
>there knowingly.
>

i put one in there after leaving it out too long waiting for the oven to preheat. obs you're supposed to just put it on the rack. came back and it was basically a cheesy paraboloid in the oven