Conversation:

Cracking article, Grommet!
I haven't looked yet but I know there are low tech ovens around which work very well in hot, sunny climates.

Basically the oven is a steel or iron box painted black outside and white or shiny inside. The food to be cooked is placed inside the box on a platform and as the sun warms the box up it cooks the food. Imagine using this in an area where there is little wood to make fires.