Melt butter in a small saucepan over low heat. Add honey, dried lavender, and mustard stirring until mixture is smooth Set aside to infuse for 15 minutes
Arrange chicken breasts, skin side up, in shallow baking dish. Pour Honey mixture evenly over chicken but reserve approx ¼ cup. Bake 35 minutes or until crisp and brown basting every 10 minutes
Meanwhile, sauté button mushrooms in butter /honey reserve and then pour mushrooms over chicken when ready to serve. Perhaps you can serve over a bed of brown rice.