In a large bowl, combine heavy cream, powdered sugar, and vanilla extract. Beat with an electric mixer until thick and fluffy, similar to whipped topping.
Gently fold in the sour cream until fully combined.
In another bowl, mix mandarin oranges, cherries, pineapple, shredded coconut, and mini marshmallows.
Add the cream mixture to the fruit mixture and stir gently until everything is well coated. This Ambrosia Salad Recipe should have a light and creamy consistency.
Cover and refrigerate for at least 1 hour before serving.