Rinse and dry the flying duck thighs.
Sprinkle with salt and paprika and place in a buttered roasting pan. Preheat oven to 200 degrees, brush duck thighs with butter and brown in oven. After about 15 minutes, turn the legs to the other side and brush a few times with the gravy. Just before the end of the cooking time of about 40 minutes, brush with a little orange marmalade to form a nice crust. Then keep warm.
Stir Grand Marnier or Cointreau, orange juice and remaining marmalade with the gravy, let it boil and reduce a little. Thicken with crème fraîche and season with a little lemon juice and sugar.
Serve with duchess potatoes and glazed chestnuts.