Preparation Sprinkle chicken breasts with salt and pepper. Melt butter in heavy large skillet over medium-high heat. Add chicken breasts and sauté until cooked through, about 5 minutes per side. Transfer chicken to platter. Tent with aluminum foil to keep warm. Add shallots to same skillet and sauté 1 minute. Add vermouth and mustard and bring to simmer. Add cream and 1 1/2 tablespoons tarragon. Simmer until slightly thickened, stirring often, about 3 minutes. Return chicken and any accumulated juices to skillet. Simmer until chicken is heated through, about 1 minute. Transfer chicken and sauce to platter. Sprinkle with remaining 1 tablespoon tarragon and serve.
Preparation Sprinkle chicken breasts with salt and pepper. Melt butter in heavy large skillet over medium-high heat. Add chicken breasts and sauté until cooked through, about 5 minutes per side. Transfer chicken to platter. Tent with aluminum foil to keep warm. Add shallots to same skillet and sauté 1 minute. Add vermouth and mustard and bring to simmer. Add cream and 1 1/2 tablespoons tarragon. Simmer until slightly thickened, stirring often, about 3 minutes. Return chicken and any accumulated juices to skillet. Simmer until chicken is heated through, about 1 minute. Transfer chicken and sauce to platter. Sprinkle with remaining 1 tablespoon tarragon and serve.