These are not the common butter cookies you are so used to seeing. This is an old German recipe given to me by my Aunt. I have been making these since I was married 31 years ago. They are rolled very thin, almost like a wafer than a cookie. The 6 egg yolks give it the richness that other butter cookies lack. I always look through websites and cookbooks to see if anyone else has a butter cookie recipe like this - I have not found one yet. I only updated the method to use a food processor instead of creaming the butter by hand. These are truly delicious and special.