Big tin can with holes (to burn charcoal)
Winter camp site
Line inside of card board box with heavy duty tinfoil using staples ensuring there are no exposed areas (trust me...important) Ensure staples on oven roof are secure to avoid dropping in food. I prefer using staple gun and limit top staples.
Use flaps for a door. Push steel rods through sides for oven rack (hanger wire fine)
Place lava rocks or ceramic brickets on bottom of box oven then place tin foil oven liner on top of spacers (if not you burn bottom of box)
Put ten small (1/4 inch) holes in top to let moisture escape
Place oven thermometor in box to try to set a record (450 is current record)
Light charcoal in tobacco can and when glowing white place on oven liner (ten white hot coals will produce aprox. 400 degree temp.)
Place frozen pizza you brought from home (easy to keep frozen since your Winter camping eh) on rack and keep door closed with whatever available.
Cook 20 min then place frozen apple pie stolen from home in oven until golden brown. Watch for bears or worse other winter campers as the aroma travels in the cold crisp air.
I have maintained an oven temp of 450 degrees for one hour before ignition