The reflector must be in a proper angle (around 60 degrees from horizontal).Whatever you are cooking(in a ziplock or in a black container) must be covered by glass or plastic wrap to retain the heat inside the box. Here I use glass.I painted Inside…
nice - do you mind sharing how you made it? I tried making one out of a car shade once and it did not work. And how do you cook - zip lock bag only, no pot?