"I love to barbeque everything. I searched far and wide for a recipe on how to grill a whole duckling on the grill and found nothing. So, I came up with this basic, easy recipe that works best when grilled on a gas-powered grill. Any residual drippings would make a delicious gravy to serve on top the final product; or make gravy with the neck and giblets."
Bring water to a boil in a saucepan; remove from heat and stir couscous into the water. Cover saucepan and let stand until water is absorbed completely, about 10 minutes. Fluff couscous with a fork.
Heat 1 1/2 tablespoons butter in a skillet over medium heat. Add onion, mushrooms, and serrano peppers; cook and stir until lightly browned, about 5 minutes. Mix in the cooked couscous and cayenne pepper.
Fill the duckling's cavity with the couscous mixture. Spread 1 tablespoon butter in a thin layer over the duckling's skin. Rub skin with basil, salt, and pepper. Wrap in aluminum foil.
Preheat grill for medium heat, about 300 degrees F (150 degrees C). Lightly oil the grate.
Place duckling on grill and cook for about 30 minutes, turning once. Remove foil; continue grilling, turning occasionally and basting with butter each time. Cook until no longer pink at the bone and the juices run clear, 25 to 30 minutes. An instant-read thermometer inserted into the thickest part of the thigh, near the bone should read 180 degrees F (82 degrees C).
Remove the duckling from the grill, cover with a doubled sheet of aluminum foil, and allow to rest in a warm area for 10 minutes before slicing. Spoon out the couscous and serve alongside the duckling.