This is a simple yogurt mousse recipe that can be made with just three ingredients, using a microwave and refrigerator. Simply heat marshmallows and milk in the microwave until melted, then mix with plain yogurt and chill. You'll enjoy a two-layered texture with a fluffy top and a smooth bottom. The whey will separate, but it's not very sour and has a refreshing taste. It's a beginner-friendly treat that's perfect for a home café or as a dessert after a meal.