I use to may these as a child with my grandmother. She called them German Filled Black Walnut Fingers. She had no recipe just did it by the "judge" method. Her and my mother would make a hundred of more each Christmas. I have experimented with many doughs but never quite get it right.
The filling was simple. Ground black walnuts, sugar and evaporated milk brought to almost boil. Let it cool.
The dough was tricky. It was light on flour, more Confectioner's sugar vs flour and heavy butter. It's this ratio that has me stumped. As the flour and 10X sugar have to be perfect otherwise the dough will just spread and you have one big cookie. I remember the dough was made into a log, wrapped in waxed paper and refrigerator for a few hours. Then sliced and the slices was rolled into a finger like shape. A well was made w/ your finger, the filling spooned in and the side folded over but not quite to the middle. Rolled in sugar and/or red and green. Baked and cooled.
Its the dough recipe that has me stumped and a few times I was almost to the right ratio but not quite. Any one that could help is greatly appreciated.