Peanut Butter Cookies Baked in a Solar Pizza Box Oven

Today we made cookies in our solar oven.

I set the pizza box on an old stove we have in the back yard, because I was too lazy to bend over and I wanted to see if the heat from the metal would make a difference.

Here is the first batch of cookies ready to cook.

Into the oven they go.  The oven thermometer  (in the upper right corner) says 78 degrees.

Here they are after 40 minutes of cooking.  I think they are done. The temperature when I took them out was 158 degrees.

Turn the box so that the reflector (lid) is facing directly into the sun.  The shadow will follow the same angle as the box.  Rotate the box as needed.  I rotated it with every new batch of cookies.

This is the second batch of cookies cooking.  In the bottom right corner you can sort of see the oven thermometer.  The temperature stayed at 158 degrees.  The second batch cooked 50 minutes and the third batch cooked 60 minutes.  The third batch was the best and could have cooked even longer.

The 12 on the left are the third batch.  The 8 in the center are the second batch and the 4 on the right are the first batch.

The kids ate them even though they were not cooked enough.

The chocolate chip cookies I baked last year were in the box on the cement. The thermometer reached a temperature of 230 degrees, so on the cement the oven goes next time.

Week 23 - Pizza Box Oven, Purchase Powdered Drink Mix

Week 23 – May 5

Build a pizza box oven. Acquire an unused pizza box of any size.  If the box is flat, put it together and close the lid.  Mark a line one inch in from all of the lid edges.  Cut open along the line on the front and two sides to create a flap.  Gently fold the flap back on the uncut line.  Line the inside of the flap with foil wrapping it to the outside.  Secure with tape.  Open the lid and line the bottom of the pizza box with black construction paper. Close the lid and roll newspaper 1” to 1 ½ “ thick.  Fit it into the inside edges and corners of the box.  Open the lid and secure the newspaper rolls in place as needed.  Do not tape to the lid.  Cut a piece of plastic wrap a little larger than the hole created from the flap.  Tape to one edge on the inside of the box.  Stretch the plastic wrap tight and tape the other three edges.  Close the box and cover the outside of the hole the same way as you did the inside.  Your oven is now ready to use.

Home food storage: purchase powdered drink mix

How to Build a Pizza Box Oven

Acquire an unused pizza box of any size.  If the box is flat, put it together and close the lid.  Mark a line one inch in from all of the lid edges  This box was so large that I made my line two inches in from all of the lid edges.

Cut open along the line on the front and two sides to create a flap.  Gently fold the flap back on the uncut line. I found it easier to fold back by using my box cutter and scoring the back line.

Line the inside of the flap with foil wrapping it to the outside.  Secure with tape.  I used hot glue to hold my foil in place.

Open the lid and line the bottom of the pizza box with black construction paper. Close the lid and roll newspaper 1” to 1 ½ “ thick.  Fit it into the inside edges and corners of the box.  Open the lid and secure the newspaper rolls in place as needed.  Do not tape to the lid.  Since my lid was cut two inches from the box edge I needed newspaper rolls that were two inches thick.  I found it easiest to roll about six layers of paper then lay that roll on another four to six layers of paper and roll again until I got the thickness I needed.  I folded the stack of newspaper edge over about 1/2 inch or less to help me get the roll started.  The shorter sections were folded  lengthwise in halves and thirds as needed and then rolled.  I hot glued the rolls of paper closed when they were the size needed and put glue on the bottom edge of the box and slid the roll in through the lid opening.  You can glue the newspaper rolls in place with the lid open, but make sure you leave a space for the lid flaps to fit between the rolls and the box.  Also from experience I learned that the loose edges of the paper rolls need to be on the bottom of the box.

Cut a piece of plastic wrap a little larger than the hole created from the flap.  Tape to one edge on the inside of the box.  Stretch the plastic wrap tight and tape the other three edges.  Close the box and cover the outside of the hole the same way as you did the inside.  I used a clear oven cooking bag instead of plastic wrap.  I hot glued one layer to the inside and one layer to the outside of the box.  When gluing the back edge of the oven bag on the outside carefully glue it to the inside bag since there is no other place to secure it to, because of the foil lined flap. 

NOTE:  All instructions I read called for plastic wrap, but I used a large oven baking bag.

Here is the completed box.  I will let you know if the hot glue withstands the heat when I use it.  June 1, 2013 was baking day and the hot glue didn't even soften.  Hooray!

NOTE:  While making chocolate chip cookies June 1, I realize that my oven needed some modifications and so did the way the cookies were cooked.

Here is the first batch of cookies into the oven.  They took about 45 minutes to cook and were still really gooey on the bottom.

This worked fine for the first batch.  Then the wind came up and kept blowing the lid up, so the stick would fall and the lid closed.  After about 10 times of that I knew I needed a better way.  I remembered reading something so I gave it a try.

I cut two long strips of cardboard and hot glued one to the box and the other to the lid.  I also cut a long piece of tie-wire and folded it into a "Z" shape.

Here is how the box looks with the wire holding it open.  Stick one short end of the wire into the slots of the cardboard as needed.  The second batch of cookies cooked for 1 hour, but they were hard on top and gooey on the bottom.  Time for another modification.

I cut four squares of cardboard to set under the edge of the pan, so that air could get under and help cook the bottom of the cookies.

Here is what the pan looked like for baking the third and last batch of cookies.  The last 5 pictures were taken several days after the baking experiment.  My house had 8 visitors at the time I was baking and the cookies got eaten as fast as they were put on a baking rack to cool.

NOTE:  You will need a hot pad to remove the baking tray from the solar cooker.

NOTE:  You can find solar cooking instructions on June 2, 2013 post.
NOTE:  On June 8, I baked cookies again and put an oven thermometer in the box and the temperature was 230 degrees the entire time.