Wash the duck thoroughly with salt, lemon, and flour, then soak it overnight in a brine solution.

Mix all the marinade ingredients with the juice of half the orange.

Stuff the duck with half the mixture and place the other half underneath it in a roasting pan. Score the duck with a knife, pour the marinade liquids over it, and close the cavity with the other half of the orange.

Add 6 1/3 cups boiling water (about 1.5 liters) to the pan and cover with parchment paper, then aluminum foil.

Roast in a preheated oven at the highest temperature for the first 30 minutes, then reduce to 350°F (180°C) and cook for 2 hours, depending on the size of the duck.

Remove the cover, strain the broth, place the duck on a rack, and broil until golden brown.