How to Make It
Place the duck breasts, orange slices, port, garlic, ginger and juniper berries in a vacuum bag. Season with salt and pepper. Seal the bag and let rest in the fridge for 8 hours.
Let duck come to room temperature, then place in a 135 degree F water bath for 45 minutes.
While the duck is cooking, make the sauce. Place the butter, shallot and spices in a small saucepan and cook for 5 minutes. Add the port. Bring to a boil, and reduce by half. Add the stock then reduce heat to maintain a simmer until the sauce is thick enough to coat a spoon. Add the orange juice and cook for an additional 5 minutes more. Season with salt and pepper, and reserve.
Remove the ducks breasts from the bag and dry with paper towels. Score the skin in a cross hatch pattern. Place skin-side down in a cast iron pan over medium-high heat.
Cook until the skin is crisp, 4 to 5 minutes. Reserve to a plate and let rest for 5 minutes. Cut and serve with the port reduction and a dollop of cranberry sauce.