a few evenings ago we attended a solar oven workshop. we learned the different types of ovens, how they work, then set about building a portable one to take home. we enjoyed the experience, (with the exception of my gigantic belly constantly getting in the way) & couldn't wait to get cooking.
we've still yet to use the cooker we built at the workshop, because thehobbit announced he would invent one. basically he lined a cardboard box (flaps included) with foil. not exactly an invention, but i didn't point that out.
this morning he put his oven to the test, with his first dish being baked apple slices. because it wasn't the oven we built, i was worried it wouldn't get hot enough to inhibit bacteria - so i gave the test a 2-hour limit.
here is the little casserole in thehobbit's oven:
& two hours later:
it worked - the dish was hot enough to warrant a potholder! thehobbit is very proud of himself, & claimed he was now a science chef.
you really should give this a try. even those of you in wintery places - it's the sun's rays, & not the temperature of the air, that cooks the food. my hotlink still is not working (oh how i love blogger), so here you go: http://www.solarcooking.org/.
** edited to add: as i don't eat cooked fruit, i wasn't a good judge of doneness. when reheating in the actual oven (for their dessert) we found they were a tad on the crispy side still. **