Melt the butter in a hot frying pan.
Add the chicken in a single layer, skin side down. Cook until the skin is lightly browned, about five minutes, then flip over and cook the other side for a couple of minutes.
Sprinkle the chicken with salt and pepper.
Add the onion and rosemary and stir.
Pour in about ¼ cup of water and half of the cream. Bring to a simmer, cover and cook over low heat for 20 to 25 minutes or until the chicken is done.
Pour in the rest of the cream. Stir. Bring to a simmer (do not allow to boil to avoid curdling) then turn off the heat. Taste the sauce, add more salt and pepper, if needed.
Toss in the parsley. Serve.