One day before: Pulse cranberries until coarsely chopped in a food processor. Add pineapple and sugar and pulse 2-3 times until fully combined.

Refrigerate for at least 1 hour. At this point, set aside half of the mixture in a separate serving bowl to serve as a relish. (IMPORTANT NOTE: If you do not want to reserve half of this to serve as a relish, only use 1 package of cranberries, 1 can of pineapple, and ¾ cup sugar.)

After the mixture has rested in the refrigerator, stir in the marshmallows. In a medium bowl, beat cream cheese on medium until smooth. Pour in the heavy cream and beat on high until stiff peaks form. Fold the cream mixture into the cranberry mixture.

Cover and refrigerate in a serving bowl overnight or for at least 8 hours.

Day of serving: Remove from the refrigerator and serve.