I was just coming to say that I did find the other recipe this morning. It's basically the same thing except it called for 2 cups of Cool Whip. The one calling for 2-1/2 cups is the one I have with my collection of favorites.

In Anne Byrn's Cake Mix Doctor cookbook, she has a recipe for Lemon Cheese Bars that's on my "try soon" list. If you're interested I'll post it (lemon cake mix, oil, eggs, cream cheese, sugar, lemon juice).