Trim excess skin from chicken (leaving skin on one side), and pat chicken dry with a paper towel.

Combine first three ingredients and sprinkle half of mixture over skin side of chicken.

Begin melting butter in pan over medium heat. Once melted increase to medium-high and add chicken skin side down.

Season opposite side of chicken while cooking and brown chicken until skin is crispy, then flip chicken and brown breifly.

Remove ckicken from pan and place on a plate. In same pan cook onion until tender.

Move onions aside and place chicken in pan along with accumulated juices. Add mushrooms and tarragon and spoon with onions over chicken.

Add water; cover and simmer until chicken is tender, about 30-40 minutes.