Susan's Tarragon Chicken

6 chicken breasts
1/2 cup diced onion
1 1/2 cup chicken broth
1/3 cup whipping cream
2 T. flour
1 tsp dried tarragon
1 T. Butter
1/4 cup watter
2 T. butter
Salt and pepper
Hot cooked rice

Place chicken in baking dish, sprinkle with salt, pepper, tarragon, and onion.  Add 1 TBS butter, broth, and water.
Cover and bake at 350 degrees for one hour.
Remove chicken to serving platter and keep warm.
Pour drippings into a heavy saucepan. Bring to a boil and reduce to 1 cup.  Pour drippings in a small bowl and add whipping cream.  Mix well and set aside. 
Melt 2 TBS butter, add flour, and cook 1 minute stirring constantly.  Gradually add whipping cream mixture.
Cook over medium heat until thickened. Add pepper to taste.  Serve chicken over rice.