Pretty cool Jim, lighweight, backcountry, quick baking. I didn't think it was possible till now. I've experimented a bit with Solar oven designs, but these aren't ideal for serious backpacking for their bulk and length of time, and limited period of use. They can be quite light, and relatively "quick" though and so can be decent for car camping. The inverted cone design one is quite fast under good conditions. I baked a large loaf of sprouted and sour doughed Kamut and Spelt bread in about an hour. Came out awesome.
Ok, my obligatory non serious and joking comment, (nothing worse than eating wet muffins, UNLESS you're talking about [kids, cover your eyes now]... oh nevermind).