Creamy Tarragon Chicken

3 tablespoons butter or margarine
6 skinned and boned chicken breasts
1 large onion, chopped
2 (8 ounce) packages fresh mushrooms, sliced
1 pint whipping cream
Sliced Monterey jack cheese
Salt and pepper to taste
1 to 2 tablespoons tarragon
Hot cooked rice or noodles

Melt butter in a saucepan over medium heat; add chicken and cook until browned, turning once. Remove from pan; reserve drippings.

Add onion and mushrooms to pan and saut