I can remember when I was young in Africa, my mother cooking meringues in the sun in the garden. I can't recall the precise technique used to prevent them being eaten by assorted animal life, but there didn't seem to be any specific equipment involved.
Solar cooking has since developed quite a long way and Solar Cookers International have trained people (mostly women) how to construct and use simple solar cookers which not only cook food while retaining essential nutrients, but can also be used to pasteurise water.
A project in Kenya is providing women with an income from making and selling the cookers. Some also sell cakes they have cooked in their own solar cooker, while others use them in restaurants. Further benefits have been an almost 50% reduction in the number of cases of diarrhoea, a 40% saving in the use of wood for fuel, and a subsequent saving of time taken to obtain and carry the wood.