Step 1

In a large skillet, cook mushrooms in 1 tablespoon of hot butter over medium-high heat about 5 minutes or until tender. Remove mushrooms from skillet. Reduce heat to medium.

Step 2

Add remaining butter to skillet. Add chicken; cook for 10 – 12 minutes or until chicken is no longer pink, turning once. Remove chicken from skillet; cover and keep warm.

Step 3

For sauce, add vinegar to skillet, stirring to scrape up browned bits. Stir in uncovered, for 2-3 minutes or until mixture is slightly thickened. Retune mushrooms to skillet, heat through.

To serve, if desired, cut each chicken piece in half horizontally to make two thin pieces. Spoon sauce over chicken.