Well finally got to try my oven idea. Based on a Swedish army svea mess kit. Used I'd guess maybe 4 ounces of alcohol total had to do a second fill up. Took maybe about 20 minutes to make a nicely flakey biscuit. Just used an instant mix. It called for milk and butter I subbed water and a bit of olive oil also gave the cup a good coat to. Made a nice crust.
Used the frying pan for the main base a few small stones to prop the canteen cup a bit covered with main pot let do it's thing.
The end product damned tasty to was a fun experiment.