This recipe comes from “Tornister-Lexikon für den Frontsoldaten” by Gerhard Bönicke, published by the Wehrmacht in 1943.
“In a pinch, bread can be baked in the mess kit. Mix 2 mess kit lids of flour (about 540 grams) with a half mess kit lid of cold water, a packet of baking powder [about 16 grams] and a half a teaspoon of salt. Knead it all together well, and form a roll that is as long as a mess kit lying flat. Roll the roll of dough in flour. Lay it flat in the mess kit and put the lid on. Carry it flat to the fire, and lay it flat in glowing wood coals or a burned down camp fire. Cover with hot ash, and allow to bake for 90 minutes. Test it with a wood sliver to see if it is done. Allow the bread to cool, and remove it from the mess kit. Do not eat until the bread has cooled.”