I live in Grants Pass, Oregon, and it gets pretty hot here in the summer — too hot for cooking indoors. When my kids have a sweet tooth, I build a box oven outdoors for making cookies. It also works great for making pies, casseroles and stews. Here's how to make one:
Find a cardboard box about 20 inches by 20 inches by 14 inches, four empty cans from corn or beans, some charcoal and a few stones. Outside, on a dirt surface or on cement, and away from any flammables, arrange the cans in a square about 5 or 6 inches apart. On the ground, in the center of the cans, put five or six charcoal briquettes and light them. Wait until the charcoal is ashy-looking, which means it is ready to cook on. Put your cookie sheet or casserole on the cans and put the box over the top of it all. Use little stones to raise the box edges about an inch, to control the heat and to allow for ventilation. Adjust the temperature with the stones — just experiment and have fun. This works. It also is great to use when camping or in case of a power outage. It even works in the snow!