We saw a woman try to bake cookies in her car, with good success, yesterday. But the gold standard of "natural" cooking would be frying an egg on the sidewalk, though car engine cooking might be a close second. Many people say that this method works.
Egg whites coagulate between 144 and 149F and yolks need an even higher temperature, so the sidewalk would have to retain a significant amount of heat for the experiment to work. Black asphalt can be 10 degrees hotter than lighter pavement, so you may want to work in the street, to increase your odds of success.
There are any number of people who have attempted to fry an egg on the sidewalk, but the problem is that many people live in places where it doesn't get all that hot. The Alberta Egg Board says that the experiment will work when the temperature is over 35C/95F, but I couldn't find any evidence of that working for anyone. The two hottest videos I found were this one, where it reached 106F just outside of San Francisco recently, and a video in Arizona, where it was also 106F. Neither worked.
I don't know if I believe that this will work, but if you've ever tried it, let us know!