Crisp Boston lettuce (to make 6 lettuce cups)

DRESSING:

1 c. mayonnaise
1/2 c. chili sauce
3/4 tsp. Worcestershire sauce
1 tbsp. grated onion
1 tbsp. chopped parsley
3/4 tsp. prepared horseradish
4 c. water
2 tsp. salt
2 lb. raw shrimp
Watercress sprigs

Cut out core of lettuce; separate leaves. Cut out any tough ribs. Plunge leaves in tepid water to float out any sand. Repeat until water is clear. Shake to release any excess moisture. Wrap loosely in towel or plastic wrap and refrigerate.

Prepare Dressing: Put mayonnaise, chili sauce, Worcestershire sauce, grated onion, parsley and horseradish in a medium-sized bowl. Mix with a whisk until ingredients are just combined. Beat until smooth. Cover dressing and refrigerate.

Meanwhile, cook shrimp. Bring 4 cups water and 2 teaspoons salt in large saucepan to boil over high heat. Add shrimp; return to boil; remove from heat. Cover; let stand for 3 minutes. Drain shrimp; cool until they are easy to handle. Using fingers, peel shrimp; discard shells.

Using a small sharp knife, slit shrimp lengthwise down the center back; remove and discard dark inner vein and then rinse shrimp to clean. (You can clean raw shrimp in the same way.) Place shrimp in a bowl; cover with plastic wrap and refrigerate.

To Serve: Arrange the Boston lettuce cups on individual luncheon plates. Remove shrimp from refrigerator; drain off any accumulated liquid and discard. Using a large French chef's knife, cut shrimp into bite-sized pieces.

Divide shrimp evenly into lettuce cups. Spoon some of the dressing over the shrimp. Garnish Shrimp Louis with sprigs of crisp watercress. Pass remaining dressing in a serving boat. Makes 6 servings. Good served with French bread and broiled tomatoes.