Start this process the night before Thanksgiving or whenever you'd like to make this. Add the cranberries to a blender or food processor and pulse just a few times to lightly chop the cranberries. Add sugar to the blender/food processor and let it sit for 15-20 minutes until the sugar and cranberries have created some juice. Pulse or blend until the cranberries are very finely chopped. Pour the mixture into a large bowl and add 1 1/2 cups mini marshmallows, stir together. Refrigerate overnight or at least 8 hours.

Remove the mixture from the refrigerator and add the rest of the mini marshmallows, halved grapes, diced apples and stir together. Whip the heavy cream to stiff peaks, then gently fold into the cranberry mixture. Enjoy immediately or refrigerate a few hours until it's time to serve. This is best the day it's made as it loses some fluff and gets more liquidy as time goes on, but can be eaten on day 2 as well.