Add the cranberries to a food processor and pulse until finely chopped. Be careful not to process them into a puree.

Transfer the chopped cranberries to a large mixing bowl. Add the sugar and stir until the cranberries are evenly coated.

Cover the bowl and refrigerate for 8-24 hours. This gives the cranberries time to soften and blend with the sugar.

Once chilled, add the pineapple, mandarin oranges, and marshmallows. Gently stir until everything is evenly distributed.

Add the whipped topping and gently fold it into the cranberry mixture until creamy and well combined.

Cover and refrigerate for at least 1 hour before serving. Keep the salad chilled until you’re ready to serve it.