Blue-Cheese-and-Walnut Dip with Waldorf Crudités

The first time I made this dip, it was delicious but way too thin. Ran off all the dippers. The second time, I substituted sour cream for the buttermilk. It was just a tad thick so I added in some half & half (I think any milk product would be fine) and it was perfect. Everything dipped well and it has become our favorite veggie / crudite dip.

This recipe is defective. I made it the day before a party, following the recipe exactly. It seemed fine and tasted good, BUT, when I took it out the next day, it was extremely thin and liquidy, to the point where it cannot be served (you could drink it, but you can't dip things in it). I am very disappointed, to say the least, given that I used all of these expensive ingredients to make it. Please post a correction, or some way to re-thicken it after it liquifies.