1st saw solar ovens at the past two RTR's, after some research I found this
https://www.amazon.com/Large-Evacua...1526651002&sr=8-2&keywords=solar+vacuum+tubes.
able to reach 400 deg F with reflector and all these items can be made, or purchased on Ebay or Amazon, for approx $ 200.00.
Have cooked pretty much any thing I would do in a regular oven. The tube is sturdy but will need protection for travel, and of course a sunny day. After getting to temp (30-45 mins) cook time is about normal oven time, lots for one and enough for two.