Chocolate cookie crumb crust enriches this easy to make but dramatic dessert. It can be prepared ahead and frozen. Thaw overnight in the refrigerator. I clipped this out of a brochure years ago and have made it several times with rave reviews! IT'S HEAVENLY! Prep time is long due to the fact that once it is assemble the mousse needs to chill for at least six hours. I have always done it overnight. I also think it is much tastier and has better consistency if it is frozen and then thawed before consumed, just personal preference.