Because of its richness, duck à l'orange always has a celebratory feel to it. My 9-year-old son Beau licks his lips in anticipation when he knows that I am making it for lunch. Many chefs recommend roasting 2 ducks for 4 people but I find that too much. I usually serve 4 to 6 people on 1 duck. At the end of the recipe, I offer 3 easy variations on the basic theme. Be sure to give them all a try.
Preheat the oven to 350°F.
Arrange the onion and carrots over the bottom of a deep roasting pan. Prick the duck skin all over with a fork (this will help release the fat stored beneath the skin while the bird roasts slowly). Season liberally with salt and pepper both inside and out, then stuff the cavity with the garlic, orange half, and thyme. Set the duck, breast-side down, in the pan and roast for 1-1/2 hours.
Transfer the duck to a baking sheet. Very carefully, pour off as much duck fat as possible from the pan into a heatproof bowl or measuring cup. Sprinkle the flour into the pan, then stir in the stock and wine. Return the duck to the pan, breast-side up. Continue to roast until golden brown, about 1 hour.
Transfer the duck back to the baking sheet. Place a fine-mesh strainer over a saucepan and scrape the dripping and vegetables from the roasting pan into the strainer. Discard the solids. Add the orange juice and marmalade to the saucepan. Bring to boil over high heat. Reduce the heat to low and simmer until it reduces to a sauce consistency, about 10 minutes.
Cut the duck in half along the backbone using poultry shears. Cut along the breastbone to split it into two pieces. Trim any parts of the rib cage off. Separate the legs from the breast. You can also separate the legs and thighs and slice the duck breast if you are inclined to do so. Divide the duck meat between four warm dinner plates, spoon the sauce over, and serve.
DUCK IN CIDER (CANARD RÔTI AU CIDRE):
Replace the orange juice with fresh apple cider and serve with sautéed apple slices.
DUCK WITH GREEN PEAS (CANARD RÔTI AUX PETITS POIS):
Substitute an equal amount of stock for both the orange juice and marmalade. Add 12 ounces of cooked green peas, thawed if frozen, to the final sauce.
DUCK WITH TURNIPS (CANARD RÔTI AUX NAVETS):
Substitute stock for both the orange juice and marmalade and add it all in Step 3 along with 12 small peeled turnips (or 6 large turnips, halved) and the chopped turnip greens.