650. Cooking in the Sun

Shabbos 9:3

If a person cracks an egg over a warm cloth, sand or the dust of the road that is heated by the sun, he is not liable even if the egg cooks because things heated by the sun are different from things heated by fire. Nevertheless, the Sages prohibited cooking with things heated by the sun as a preventive measure against the possibility of cooking with things heated by fire. Similarly, if someone cooks using the Tiberias hot springs or a similar heat source, he would not be liable. If a person cooks on a fire but the food is already completely cooked or it does not require cooking at all, he is not liable.

Shabbos 9:4

Let’s say that person A brought fire, person B brought wood, person C brought a pot, person D added water, person E added meat, person F added spices, and person G stirred it. In such a case, all the participants are liable for cooking. This is because anyone who performs an act that is necessary for the cooking process is considered to have performed the labor of cooking. On the other hand, let’s say that person A put down the pot, then along came B and added water, then along came C and added meat, then along came D and added spices, then along came E with fire, then along came F and put wood on the fire, and finally along came G and stirred the pot. In such a case only F and G would be liable for cooking.