Dissolve gelatin in boiling water. Add pineapple to gelatin mixture, stirring well. Chill until mixture is consistency of unbeaten egg white.
Combine next 3 ingredients; fold into gelatin. Pour into a lightly oiled 9-cup ring mold; chill until firm. Unmold on lettuce leaves, and garnish with a dollop of mayonnaise, if desired.
Oxmoor House Homestyle Recipes