1/2 c. oil
1/4 c. fresh lemon juice
1/2 tsp. freshly ground pepper
6 (8 oz.) chicken breasts, skinned, boned
3 tbsp. tarragon vinegar
2 tbsp. dry white wine
1 tsp. tarragon
1/2 tsp. freshly ground white pepper
16 tbsp. (2 sticks) butter
2 tbsp. Dijon mustard
Lemon slices, parsley sprigs (garnish)

Combine oil, lemon juice and pepper in shallow dish. Swirl chicken in mixture to coat. Cover with plastic wrap and marinate in refrigerator for 30 minutes.

Meanwhile, combine vinegar and wine in heavy small saucepan. Boil over medium-high heat until liquid is reduced to 2 tablespoons. Remove from heat; add tarragon and pepper.

Whisk in butter 1 tablespoon at a time, blending thoroughly after each addition. Place over low heat; continue whisking until sauce is thickened. Whisk in mustard. Keep warm.

Prepare grill. Drain chicken well. Grill 3-4 minutes on each side. Serve sauce separately. Yield: 6 servings.