Wadi Musa feeds tour groups, so the good decisions are made away from the buffet line and before the gate opens.
Tourism Street
The run of restaurants between the town and the park entrance, most of them mezze-and-grill places sized for coach parties. It is where you will eat most nights, and most of the kitchens here are dry.
Petra Kitchen
A cooking class rather than a restaurant: you make five or more dishes — hummus, baba ghanoush, maqluba — and then eat them. On Tourism Street, minutes from the park entrance, inside the Petra Boutique Hotel.
Mansaf and maqluba
The two dishes worth asking for by name. Mansaf is lamb cooked in jameed, a dried fermented yoghurt, over rice and eaten by hand; maqluba is the rice, meat and vegetable pot turned out upside down at the table.
Ask for breakfast before six
Nothing in Wadi Musa is open when the gate opens, and there is no food between the visitor centre and the basin restaurants deep inside the site. Most hotels will do an early or packed breakfast if you ask the night before.