This picture of chef Vered Zaada frying an egg on a black car bonnet was published by the BBC during Britain’s 2006 heat wave (though I do wonder what her left hand is doing on the car.; looks a bit staged to me).
It takes at least 70ÂșC to get egg protein to coagulate. A black car surface can easily reach that in direct sunlight, but as soon as the egg hits the surface it will rapidly cool the thin steel underneath. That means that to continue cooking the egg, heat has to be conducted in from the surrounding metal. Steel is not a good heat conductor, so it’s almost impossible to get enough heat all the way into the middle of the egg. Most videos of people trying this show some feeble cooking of the white around the edges, as you would expect, but the center just sits there uncooked. It can be managed by moving the egg along to new hot spots, but that tends to scramble the egg (which feels a bit underhanded, don’t you think?).