Step 1

Clip (or stand) sous vide machine to a tall, large pot. Fill pot with warm water to height according to manufacturer’s instructions (keep in mind that chicken when added will cause water to rise).

Step 2

Season chicken lightly with salt and pepper. Place chicken in bag and add pesto; turn to coat.

Step 3

Vacuum-seal or partially close resealable bag, getting as much air out as possible to keep bag from floating, and place in water bath. If using a resealable plastic bag, push down into water to submerge (this will push more air out of the bag) and fully close. To ensure proper cooking, contents of the bag need to be completely submerged in water. Turn on machine and heat water to 145°.

Step 4

Using a small clip, secure top edge of resealable bag to rim of pot, positioning it opposite of the machine’s water outlet; as the water circulates, it will help keep the bag submerged. If using a vacuum-sealed bag, you may need to set a small plate on top to prevent floating. Cook chicken, maintaining water bath at 145°, 2½ hours. Remove bag from water bath and let chicken rest in bag 10 minutes (this lets the chicken absorb some of the juices).

Step 5

Transfer chicken to a cutting board and slice. Serve with pesto cooking liquid (it makes for a great sauce to go with chicken, especially tossed with some pasta).

Step 6

Do Ahead: Chicken can be cooked in water bath 4 days ahead. Keep sealed in bag and chill, or freeze up to 1 month. Enjoy cold or reheat with sous vide machine at 100° until warmed through, about 1 hour, before serving.