Preparation Place chicken breasts between sheets of waxed paper and pound to even 1/2-inch thickness. Peel off paper. Sprinkle chicken breasts with 1 teaspoon tarragon, then salt and pepper. Melt butter in heavy medium skillet over medium-high heat. Add chicken breasts to butter; saut
 until brown and cooked through, about 4 minutes per side. Transfer chicken breasts to plates. Add shallot and remaining 2 teaspoons tarragon to drippings in skillet. Sauté over medium-high heat until shallot begins to soften, about 2 minutes. Add grapes, wine and cream and boil until sauce thickens enough to coat spoon, about 5 minutes. Season sauce with salt and pepper. Spoon sauce over chicken.
Preparation Place chicken breasts between sheets of waxed paper and pound to even 1/2-inch thickness. Peel off paper. Sprinkle chicken breasts with 1 teaspoon tarragon, then salt and pepper. Melt butter in heavy medium skillet over medium-high heat. Add chicken breasts to butter; saut
 until brown and cooked through, about 4 minutes per side. Transfer chicken breasts to plates. Add shallot and remaining 2 teaspoons tarragon to drippings in skillet. Sauté over medium-high heat until shallot begins to soften, about 2 minutes. Add grapes, wine and cream and boil until sauce thickens enough to coat spoon, about 5 minutes. Season sauce with salt and pepper. Spoon sauce over chicken.