Wash the duck, pat dry and remove excess fat from the abdomen. Then prick the skin all around with a wooden stick. Rub the bird inside and out with salt and pepper. Peel the apples and cut into pieces. Clean and slice the spring onions, mix with the apple pieces and stuff the duck with them. Pin or sew up the opening.
Now put the prepared duck on a grill skewer and secure it with the retaining clips.
Prepare a marinade from orange juice, sherry, soy sauce, honey and cayenne pepper and brush the duck with it.
Grill the duck in the gas grill while rotating for approx. 2 hours or a little longer, placing a deep drip pan underneath and collecting the juices. Brush with the marinade again and again.
For the sauce, let the cane sugar caramelize briefly in a saucepan and deglaze with the orange juice. Now add about 8 tablespoons of the gravy and reduce the amount by about half. Turn down the heat. Now beat the ice-cold butter, cut in flakes, into the sauce, do not bring to the boil again. Season to taste with salt and pepper.
Serve the finished duck in one piece and carve it at the table. Serve with the sauce and - if you like - the remaining gravy.
The side dishes are a matter of taste - red cabbage and dumplings would be classic, while camping, fresh baguette and a salad are also good.
Note: I cooked the duck this way in a gas camping grill (from Cramer) and it only began to sweat after just under 1 hour - it took about 2 1/4 hours until it was crispy and well done . It`s probably faster in an electric grill with the door closed.