My cousin Sarah brought this to Sunday lunch and everyone begged her for the details. It is perfectly sweet and melts right in your mouth.

Chill to set: Transfer the finished rainbow fruit fluff to a large serving dish—something shallow and wide works well so you can scoop into it easily. Use the back of a spoon to create a softly scooped top with gentle swirls; this gives it that inviting, homemade look. Cover the dish tightly with plastic wrap and refrigerate for at least 2 hours, or up to 8 hours, to let the flavors mingle and the texture set.
Serve: Just before serving, remove the plastic wrap and, if you like, garnish with a few extra pieces of fruit or a light sprinkle of coconut. Set the dish on a clean black or dark countertop or serving surface to show off the colors and contrast. Use a large spoon to scoop generous, cloud-like portions into bowls. The fluff should be cool, creamy, and soft enough to melt in your mouth with each bite.
Variations & Tips
For a more classic, ultra-sweet potluck version, you can replace the homemade whipped cream with one (8-ounce) tub of frozen whipped topping, thawed; simply fold it into the fruit and marshmallow mixture as directed. If you enjoy a tangy note to balance the sweetness, fold 1 cup of vanilla or plain Greek yogurt into the whipped cream before adding it to the fruit—this turns the dish into something between a dessert and a creamy fruit salad. To lean into the rainbow theme, swap in different fruits: add 1/2 cup of drained pineapple tidbits, sliced kiwi, or blueberries, keeping the total fruit amount roughly the same so the ratio of fruit to cream stays balanced. For a nutty twist, sprinkle in 1/2 cup of chopped toasted pecans or walnuts when you add the marshmallows; this adds texture but will make the dessert a bit less “melt-in-your-mouth” and more crunchy, so choose based on your crowd. If you need to make it ahead, assemble the fruit and marshmallows in the bowl, cover, and refrigerate; whip and fold in the cream up to 4 hours before serving so it stays light. To make it slightly lighter overall, reduce the powdered sugar to 2 tablespoons and add a squeeze of fresh lemon juice to the fruit mixture before folding in the cream—this brightens the flavors without sacrificing that soft, cloud-like texture.