Built the first one 40 years ago, for my mother who didn't want to use the oven on hot days. When she died, I got it back and still have it. The reflective stuff is from a discarded wildfire shelter.
Here's a similar one built for a recycling contest (it won). The top is polycarbonate instead of glass.
GoSun sells a range of solar stuff. Here's their Pro Cooker, based on an evacuated glass tube originally designed for heating water. I built a simple mount to aim it sunwards.
Bought a kit and built a reflector with a plastic bucket.
Just got a GoSun Fusion cooker, which is larger and has an electric element so it works after dark or on cloudy days, powered by a battery.
Loading it with stuffed red bell peppers and rice, which cook in a bit over an hour.