In this healthy, creamy mustard chicken recipe, thin-sliced chicken breasts (sometimes labeled chicken cutlets) cook quickly and are delicious smothered in a velvety, light mustard sauce and garnished with fresh chopped sage. If you can’t find chicken cutlets, cut boneless, skinless chicken breast into 4-ounce pieces and place between pieces of plastic wrap. Pound with a meat mallet, rolling pin or heavy skillet until flattened to about 1/2 inch thick.