A friend of mine made these really delicious cookies a few days ago. When I asked how they became to be so good, she told me the secret ingredient: Nutella. That explains a lot.
So I did a bit of googling, and found this website: http://nutellacookies.org. As stated by the sites adress, it has a few recipes with Nutella in it, and even with peanut butter. And to make this discovery even more perfect, the recipes turn out to be quite easy!