Drain crushed pineapple; reserve 2 tablespoons juice. Set aside.
Place crushed pineapple, lemon juice, lime juice, sugar and reserved pineapple juice in blender or food processor container. Cover; blend until smooth. Stir in cherries or marshmallows or chips, if desired.
Pour into two 1-quart freezer zipped bags. Store bags flat in freezer. Freeze about 1-1/2 hours or until slushy.
Stir gently pineapple slush into whipped cream until just blended, in large bowl. Return to freezer until completely frozen, about 1 hour. Serve.