Build a wooden box lined with tinfoil to cook pizzas, naan bread etc.
Wood, power tools, hinges, screws, baking trays.
The idea is to create a wooden box lined with tinfoil. On the bottom, you place some embers (on a baking tray), and half-way up, your baking tray/grill with the food to cook. Shut the door, leave for 20minutes, and have some oven cooked food.
We've successfully cooked pizzas that turned out phenomenally well!
MDF worked fine, so cut it into the right size for your trays, glue/screw it together into a box, leaving one side attached with a hinge. Then make some "rests" for the cooking tray.
Line the whole thing with several layers of tinfoil.
When using it, put some stones or similar on the bottom just to keep the tray of embers off the bottom to reduce the change of burning through the tinfoil.