Add water to the sous vide container or a large pot, set the Sous Vide Precision Cooker to 135°F (57°C). This is my preferred doneness with medium-rare meat, and if you’d like to cook it more or less, follow the temperate guide in the post above.
Score Duck Breasts: Place the breast on a cutting board skin side up. Using a sharp knife, score the skin in 1/2 inch intervals with a crosshatch (diamond) pattern. (Be sure to cut through the fat, but not the meat.)
Season the breast: Season the skin side with salt only. Then flip the breast, and season the flesh side with salt and pepper.
Sous vide duck breast: Place the seasoned duck breast in a zip-lock bag, vacuum seal it using “water displacement” technique: seal all but one corner of the bag, and slowly place it into a container with water. Make sure everything below the zip-line is covered by water. Then seal the rest of the bag. (If you use a vacuum sealer, seal the bag on the dry setting.)
When the water has reached the set temperature, lower the bag slowly into the water bath and make sure the breasts are fully submerged.
Cook for 2 hours. (This is my preferred cooking time, but you can reduce it to 1 hour if you are in a hurry, or cook as long as 4 hours.)
Sear duck breasts: When the timer goes off, remove the duck breasts from the bag and carefully pat dry with paper towel. (Make sure that you pat dry the breast very well, otherwise it will interfere with the searing.)
Heat a non-stick skillet over medium-high heat. When hot, add duck breasts with skin-side down in the pan. Remove from heat when the skin is evenly browned, about 5-8 minutes. It’s ok if you find the center of the meat still pink. (If you find there’s too much water coming out of the breast, you can pat dry it one more time, and drain the liquid in the pan. Then continue searing.)
Flip the breast and quickly sear the flesh side for about 30 seconds.
Let duck breasts rest for 3 to 5 minutes.
Slice the breast, serve with potatoes, and drizzle with red wine sauce or berry sauce.