Almost anything you can cook in a conventional oven, you can cook in a solar oven.
Find two boxes. One should fit inside the other with a 2- to 3-inch space on each side. (This can vary slightly - the space will be filled with newspaper.)
Line the bottom of the large box with crumpled newspaper.
Place the smaller box inside the large box.
Fill the space between the sides of the two boxes with crumpled newspaper.
Line the sides of the inside of the smaller box with aluminum foil. You can use a non-toxic tape or fold the edges of foil over the top of the box to hold it in place.
Line the bottom of the inside of the smaller box with black construction paper to absorb heat.
Lay a piece of cardboard on top of the large box and trace the shape of the box onto the cardboard.
Add 2 inches around the trace line and cut out to make a reflector.
Cover the cardboard piece with aluminum foil. Smooth out any wrinkles and secure the aluminum foil to the cardboard with non-toxic glue or tape.
Staple the reflector to the outside back of the large box.
Situate the oven with the box opening up and the reflector facing the sun for maximum heat.
Place food to be cooked in the solar oven. (See "How to Use a Solar Oven," under Related eHows.)
Stretch clear plastic wrap across the top of the large box. Secure the plastic with tape around the entire box.
Cooking time is about twice as long as in a conventional oven.
Preheating takes about 30 minutes.
Use bigger boxes for a larger oven.
A small pizza box oven is good for kids to make s'mores or mini-pizzas.