"These German Christmas cookies are similar to shortbread and we bake them every year in December. The recipe makes a pretty large amount and they are pretty quick to make, since you only have to cut the dough, so perfect for last minute baking."
Beat 3/4 cup plus 2 tablespoons butter in a large bowl using an electric mixer until creamy. Add 3/4 cup plus 4 teaspoons confectioner's sugar, egg yolk, and salt; beat until smooth. Knead in 2 1/4 cups plus 2 tablespoons flour and 3/4 cup plus 2 tablespoons walnuts.
Shape dough into 2-inch thick rolls and press them into rectangles using a flat item like a cutting board. Wrap in plastic wrap and refrigerate until firm, about 1 hour.
Preheat oven to 375 degrees F (190 degrees C).
Cut dough into thin slices and lay them on an ungreased baking sheet.
Bake in the preheated oven for 10 minutes. Reduce heat to 250 degrees F (120 degrees C) and bake until very lightly browned, about 5 more minutes.
Remove from the baking sheet and cool on a wire rack, about 20 minutes.