Jo Kennard in Australia has developed a retained heat cooker the Easy Oven, and has developed an excellent table of recommended cooking times and recipes to go with it.
Inspired by traditional Haybox cookers, and made from modern materials, the EasyOven saves between 86% - 90% of energy used while cooking meals, keeps food hot (or cold) for up to 3 hours. It was field tested during the Christchurch earthquakes and the Brisbane floods, and it is at home both in rural kitchens and in suburban potlucks. For More information see http://www.easyoven.com.ausneakers
