Combine heavy cream, powdered sugar, and vanilla extract in a large bowl. Use an electric mixer to beat until mixture is thick, billowy, and the consistency of Cool Whip.
Stir in sour cream.
In a separate bowl, stir together oranges, cherries, pineapple, coconut, and mini marshmallows.
Add whipped cream/sour cream mixture and stir until completely combined.
Cover bowl and chill in refrigerator for at least 1 hour before serving.
¹I like to use the rainbow/fruit flavored mini marshmallows for more of a tropical flavor, but classic white mini marshmallows work just as well!
Some people like to add nuts to their ambrosia salad. ¾ cup of coarsely chopped nuts such as pecans or walnuts would make a great addition.
Storing Ambrosia Salad
I recommend making Ambrosia Salad 1-24 hours before you intend to serve, for best flavor and texture. However, Ambrosia Salad will keep in the refrigerator for up to 3 days (make sure to store in an airtight container). I do not recommend freezing.