Place chicken in a heavy pot. Add cold water so it comes up 1 inch above the chicken. Add the rest of the ingredients. Turn the heat to medium-high heat and keeping a close watch on the pot. As soon as the water just starts to boil, turn the heat down to the lowest possible simmer (160º-180ºF). The water should be shimmering as if it's about to boil, but not bubbling. Set the timer and cook the chicken, partially covered to help maintain a constant temperature, for 10-14 minutes. Timing will depend on the size and thickness of the breasts. Check for doneness after 10 minutes. (See notes below for how to check for doneness)
Immediately remove the chicken from the cooking water and let it cool for a few minutes before slicing, dicing or shredding it. If you're not using it right away, store poached chicken in an airtight container in the fridge for up to 4 days.
