Damper (https://en.wikipedia.org/wiki/Damper_(food)) is an Australian tradition that can be cooked on nothing but campfire ashes.
I'm not sure about alum foil, but sounds worth a try. the melting point is high enough, but so thin... There's a (NZ) maori tradition of roasting by wrapping meat/veg in leaves (foil would do), then burying in coal and heated stones. Might work for bread, too?
If the idea of an oven is uniform heat (idk, is it? IANAC), that buried in coals & stones seems pretty good, with foil to keep ash out. If hot air is part of an oven (again, idk), maybe a little space at the top could constructed too.
When I've attempted damper, I've lost a lot, in the form of charred skin. Maybe I'm doing it wrong.
I think they just feel that way because we hold them extended with one arm. In a backpack with tonnes of other stuff I doubt it would be that noticeable. I've mostly used much thinner pots and found they work well though, the al-foil approach too.
> If the idea of an oven is uniform heat (idk, is it? IANAC), that buried in coals & stones seems pretty good, with foil to keep ash out. If hot air is part of an oven (again, idk), maybe a little space at the top could constructed too.
The main thing is you want the charcoal to cool a bit first, not red hot straight from the fire, then the thickness doesn't matter and it will be uniform enough.
There's a chance I could be forgetting some stuff here because it's been a long time. If you've got a wood fired BBQ (not many do anymore) they make an ideal testing ground every time you have a BBQ, that's where I learned my craft as a kid.
Cast iron dutch ovens weight about 30lbs. How much do you normally carry in your backpack, that 30lbs would not be noticeable?
There's a horizontal panel to support the food, a 45-degree lower panel to reflect heat upward into the food, and a 45-degree panel to reflect heat downward into the food. And then there's some wirework to keep it upright next to your fire.
It all folds flat and slides into the pocket of your pack normally reserved for the ballistic armor plate. Maybe it isn't designed for that, but few other things would fit in there. Maps, perhaps?
There may be another way to rig the reflectors to reconfigure as a solar oven.
The arm increases weight percieved, but I really mean "ultra-light" bushwalking. e.g. my tent (a "bivvy") was less than 1kg. So... even a regular saucepan or frying pan is over-the-top in weight! Alum foil is more "ultra-light". :)