Cream together the butter and sugar in a medium bowl. Add vanilla extract and egg yolk; mix until fluffy. Stir in flour. Refrigerate dough for 2 hours.

Preheat oven to 300°F (150°C). Grease cookie sheets.

Roll dough into teaspoon-sized balls. Dip balls into chopped almonds and place on cookie sheet 1 inch apart.

Make an indention in each ball with a finger and fill with raspberry jam using a teaspoon or pastry bag.