This really did make amazingly tender and tasty chicken breasts. I agree with DoraV though, not sure where the butter comes in.
Just made this and the chicken turned out great. Used 3 breasts, but the same amount of other ingredients (extra parsley/thyme), and ended up cooking it 24 min. to get it to 160 deg. Tricky figuring out what temp. the burner should be at to maintain the water temp. - I switched to med. partway through. I set the chicken on a cutting board to cool some, then shredded it and put it in a bowl with a little stock - I did not cool in the stock. Will be making a nice bowl of chicken salad with it!