Beat together butter and sugar in a mixer bowl.

Add vanilla and egg yolk. Mix well.

Mix flour and salt. Add to butter mixture and mix well.

Cover and refrigerate at least 1 hour.

Heat oven to 325°F.

Shape dough into 1-inch 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 1 inch apart on ungreased cookie sheet. Press thumb in the center of each to make an

indentation.

Bake until light golden, 15 to 18 minutes.

Cool on wire racks.

Fill indentation with a small amount of raspberry jam.