- Place 4 cups cold water and 2 large chicken breasts (about 1 lb., 4 oz. total) in a large saucepan. This water-to-meat ratio is important; if you want to cook more chicken, add another 2 cups water per breast (enough that they’re fully submerged by an inch). Season the water with 3 Tbsp. Diamond Crystal or 3½ tsp. Morton kosher salt (if adding more water, increase amount of salt accordingly).
- Bring the water to a gentle boil over medium heat. As soon as the surface of the water starts to roll, flip the breasts over with tongs, remove the pot from heat, and cover with a tight-fitting lid. The chicken breasts will continue to poach gently in the hot water.
- To test the meat’s doneness, insert the probe of an instant-read thermometer into the thickest part of the chicken breast—once it registers an internal temperature of 150°, remove chicken from the water. This will usually take about 5–10 minutes, but it all depends on the size of the chicken breasts. (The total cook time will range from 10–20 minutes.)
- Let the poached chicken breasts rest on a cutting board for at least 5 minutes (this resting time allows the juices to settle and redistribute, ensuring juicy chicken). Slice chicken into ¼"-thick slices. It might be the tiniest bit pink inside, which is okay as long as the proper temperature has been reached. (And is much more favorable than gray, rubbery overcooked chicken.)
Source: https://www.bonappetit.com/story/how-to-poach-chicken-breasts