Cheese-Stuffed Bacon-Wrapped Chicken Breasts

Heat oven to 350 °F. In 8-inch skillet, melt butter over medium-high heat. Add onion, mushrooms and thyme; cook 2 to 3 minutes, stirring occasionally, until tender. Set aside. Between pieces of plastic wrap or waxed paper, place each chicken breast; gently pound with flat side of meat mallet or rolling pin until about 1/4 inch thick. In medium bowl, mix mushroom mixture and Gruyère cheese until well blended. Place heaping 1/4 cup mushroom mixture on center of each chicken breast. Roll chicken over filling, tucking ends to enclose filling; secure with toothpick, if necessary. Carefully wrap each chicken breast with 3 bacon slices. Place in ungreased 8-inch square (2-quart) baking dish. Bake 40 to 45 minutes or until chicken is no longer pink in center.