to 18 minutes
1. Beat together butter and sugar in a mixer bowl. Add vanilla and egg yolk. Mix well.
2. Mix flour and salt, add to butter mixture and mix well. Cover; refrigerate at least 1 hour.
3. Heat oven to 325 degrees. Shape dough into 3 cm balls. Beat egg white lightly in a small bowl. Put nuts in another small bowl. Dip each ball into egg white, then roll in nuts. Put balls 3 cm apart on ungreased cookie sheet. Press thumb in the center of each to make an indentation.
4. Bake until light golden, 15 to 18 minutes. Cool on wire racks.
Fill indentation with a small amount of raspberry jam. Faye Kuhn, of Earlville, Illinois, recalled growing up in the tough times of the '40s: "Despite the lack of finances, no holiday was ever ignored in our household. Christmas, however, held the highest of honors. . . We all boarded the train and off to the city we would go. We would arrive home loaded with 'Evening in Paris' cologne, mittens, socks, handkerchiefs and coloring books bought at Kresge's and Woolworth's. Mom would then visit the local A & P for turkey, cranberries, sweet potatoes, fresh ground coffee, nuts, apples, oranges and one pound of butter to baste ol' Tom with. However, there was one thing my mother didn't do in those days and that was to bake Christmas cookies, for neither time nor money allowed such a luxury." But when her mother retired, she started baking Christmas cookies, Kuhn recalls. The family wanted her to make the thumbprints, yet no one knew the name or the recipe. "Mother put on her coat, crossed our back yard and knocked on our neighbor's door. She returned somewhat later, victorious, with recipe card in hand." from the Chicago Tribune annual Food Guide Holiday Cookie Contest December 8, 1988 ----