Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
     1/2  cup           oil
     1/4  cup           fresh lemon juice
     1/2  teaspoon      ground pepper
   6                    chicken breasts halves
   3      tablespoons   tarragon vinegar
                        skinned and boned
   2      tablespoons   dry white wine
   1      teaspoon      dried tarragon
     1/2  teaspoon      white pepper
   1      cup           butter
   2      tablespoons   strong Dijon mustard
                        ***Garnish***
                        lemon slices
                        parsley

Preparation:

Combine oil, lemon juice and pepper in shallow dish. Swirl chicken in mixture to coat. Cover with plastic wrap and marinade in frig 30 minutes. Meanwhile combine vinegar and wine in heavy small sauce pan and boil over medium high heat until liquid is reduced to about 2 Tablespoons. Remove from heat and add tarragon and pepper. Whisk in butter on tablespoon at a time blending thoroughly after each addition. Place over low heat and continue whisking until sauce has thickened slightly. Whisk in mustard. Set aside and keep warm. Prepare charcoal grill. Drain chicken well. Grill three to four minutes on each side. Arrange on heated platter. Garnish with lemon slices and parsley. Serve warm sauce separately.