The Panel-Box Cooker combines the technologies of both a solar panel cooker and a solar box cooker. The cooking enclosure assembles to become a rigid box, and uses part of the panel reflectors to provide the back and the bottom of the enclosure. The reflector panels are fabricated from plastic flute board, which hinge together using plastic zip-ties, and are covered with reflective material. The bottom, sides and front panels hinge together as one piece, and the two-piece rear reflector as another. Both can be folded flat without further disassembly. The rear reflector uses a notched slot to connect to each of the cooker sides. Once the panels are in place, four rigid pieces of twin-wall polycarbonate notch into the reflector panels forming the cooking enclosure. The assembled enclosure is