In a heavy saucepan over low heat, melt marshmallows and milk. Remove from the heat. Cool, stirring occasionally. Stir in extract. Fold in pineapple and whipped cream.

Combine cracker crumbs and butter. Press 1-1/2 cups into a greased 13-in. x 9-in. pan. Spread with the pineapple mixture. Sprinkle with the remaining crumb mixture. Refrigerate for 2-3 hours before serving. Yield: 12-16 servings.