a cookie is a cookie is a cookie

I just failed my first attempt to make cookies. I got the non-bake cookie recipe from Demoree last week. The ones she made were so good that I couldn't help giving it a try.

First, they are too salty. Well, I can accept that. The reason might be the peanut butter I used. It already has salt in it, so I shouldn't add extra salt to the mixture.

The real problem is that the "cookies" intend to keep their liquid form and I don't know why. In the last couple of hours I poked them at least dozens of times. And finally I announced to my parents that I failed. Before that I just kept telling them it took time for the cookies to solidify.

As an engineer, I thought into it and also sent an email to Demoree for possible solutions. Could it be that I used the reduced-fat milk instead of whole milk? Or I didn't boil the mixture hard enough? Or I just don't have the talent to make cookies?

I guess none of the conclusions should be made until I try at least several more times.