YOU WILL NEED:
a sunny day
larger cardboard box
bubblewrap or newspaper
clear plastic or cellophane
cookie dough recipe
Tip: Do not skimp on your tape — making the oven as airtight as possible is key to trapping in the heat, so make sure you seal any possible gaps with the tape.
Your shoebox will form the inner part of the oven where you cook, so you’ll need to line the inside with glued-on black paper. Darker colors absorb more heat from the sun, so black is going to get the hottest of all.
Now take your bigger box, the outside of your oven, and insulate it to stop the heat escaping. You could use bubble wrap or scrunched-up newspaper to do this job. You’ll need to leave enough room for your shoebox to sit in the center at the top. Now just cut the uppermost flaps of your larger box so they can be taped down to form the top of the oven, leaving only the black inside of the shoebox on show.
Use three sections of cardboard, bent lengthways, and tape them together to form three sides of a lid for the oven. Ensure they fit nice and snugly. Now cut your clear plastic or cellophane the same size as the top of the large box and tape it down along the back edge. Place your lid on top with its longest side running along the front of the box and tape the end of the two sides onto the rear of the box. Now open up your lid and tape the other three sides of the plastic to its inside, making sure to pull it tight.
Finally, to reflect as much light (and heat) as possible, cut a large section of card and cover it with aluminum foil. You can then tape this to one side of the box and use a stick to prop it into the best position. If you want to increase the light even further you can add another reflector on an adjacent side.
Now you can get cooking. Experiment with the best place to put your oven and angle your reflector before leaving it to heat for half an hour. Cut your raw cookie dough and place two or three flattened circles into the center of the oven and quickly shut the lid. Leave until cooked (this could take two or three hours depending on how much sun you have and how airtight you’ve managed to make your oven).