A small one
I know it was 4 minutes because I set the oven to pre heat and it takes 4 minutes
I cut the onion in half thinking that it would be simple, then spent that whole time chipping off shards of skin with my thumb nail which got it under the nail, got the skin stuck to my fingers with the onion juice and gouged out bits of the onion with my thumb nail and the knife where I was trying to lift off the skin
I have no idea how they do it on these tv shows where they just peel it off like they're taking off a t shirt or something.