Sun baked foods stay moist, the natural internal juices do not bake out, resulting in a superior, moist taste and much less shrinkage. Cooking times are close to the same as those in a conventional oven. Because the sun is often trying to run away and hide behind clouds, cooking times can vary. At times it may take a little longer. No, but dark, thin-walled pots with lids work best.
Dark pots change the light from the sun into heat energy.
Lids are important because they hold steam in the pot. If a lid is not used the steam will dissipate much of the heat. Shiny aluminum pots and pans cause light to be reflected out thereby reducing the oven's temperature. Glass casserole dishes with lids also work well. For baking cakes, breads, cookies, and pies, dark cookie sheets and baking tins work best.