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.)
Most car trips don’t warrant a stopping for food.
There is very little space in the engine compartment on modern cars.
The engine usually run around 90°C which is not enough to boil water. You could use the exhaust pipe but that is harder to reach.