In the 1970’s and 1980’s there were several books the either had characters that did it or promoted it.
Why is there no cooking tray in my new car’s engine bay?
Is it dangerous? (It would be less physically dangerous if there was a specific spot for it.)
It is very hard to time your trip so that you get there when everything is done. those who try it either have overcooked food or have to drive around for a while after they get there for the meal to finish.
in the end it works but not well enough to do it. Even truckers who eat on the road find separate appliances better.
Those are good points.
I had been thinking of partly cooking on the engine, and finishing in the oven. (Use case is baking something that needs 90 minutes in the oven.) Actually moving hot food is an issue, though one we deal with normally when baking.