Perfect for summer, these parfaits are light and refreshing. They can make an elegant finish to your meal. Instead of chocolate graham crackers you could use crushed Oreos, but I think the richness of the Oreo overwhelms the light mousse flavor. Cooking time is Chill time. Note: If you chose a smaller glass, such as a champagne glass, you will get 6 servings instead of 4 and will need to adjust the layering amounts accordingly.