http://www.pureenergysystems.com/store/Sun_Oven/
I have used a Sun Oven for years and have used it to cook anything you can make in an oven including baking bread, cookies, cornbread, brownies, rice, chicken, pork roast. I have had people come and knock on my door to ask what that thing is in my yard.
Solar ovens are great for third world countries, places where women search for hours for firewood to use for cooking. There are places like Haiti which have been virtually deforested. A solar oven may also be used to make water safe to drink which is also important in third world countries.
Solar ovens come in different sizes and designs and have been made for many years as a science project. They are not only green, they are fun to use. Winter or summer, all you need to make it work is sunshine.