1 (6 oz.) pkg. lime Jello
1 (20 oz.) can crushed pineapple
2 c. buttermilk
1 (9 oz.) carton Cool Whip

Bring pineapple (undrained) to boiling point. Pour over Jello and dissolve. Add buttermilk. Refrigerate until it begins to congeal. Fold in Cool Whip. Pour into bowl and refrigerate.