1/2cup low sodium chicken broth OR (1/2 cup dry Sherry)
1/3cup heavy cream
2tablespoonsDijon mustard OR (1 tablespoon Dijon mustard and 1 tablespoon stone ground mustard)
Cut chicken breasts in half horizontally. This will help to thin out the chicken breasts, and they will cook faster. If the breast pieces are not uniform you may want to place the pieces within plastic wrap and you may want to pound the breasts into uniform thicknesses. Salt and pepper to chicken on both sides.
Heat a large skillet to medium heat and add olive oil and butter. Heat the oils until the butter foams and becomes fragrant. Place chicken pieces into skillet. Cook on both sides until the chicken is done. Remove chicken. Add chopped garlic and saute until the garlic becomes fragrant.
Add either chicken stock or dry Sherry. Deglaze the pan by scraping the browned bits from the bottom of the pan. Add heavy cream and mustard. Stir the sauce until it is thoroughly mixed. Serve chicken and spoon sauce over the chicken. If you want to reheat this dish I recommend that you store the sauce and the chicken in separate containers.