Separate the eggs and save the whites in a small bowl to coat each ball of dough.

In a large mixing bowl, beat room-temperature butter by hand or with an electric hand mixer on medium speed for 30 seconds.

Add about half of the flour, sugar, egg yolk, and vanilla. Beat until combined.

Beat in remaining flour. Stir until dough forms.

Cover and chill for 1 hour or until easily handled.

Using a small cookie scoop, shape into 1-inch balls.

Roll balls in egg whites, then in minced nuts.

Place one inch apart on parchment paper lined cookie sheet.

Press centers with your thumb or the back of a measuring spoon.

Bake at 375 degrees F for 10-12 minutes or until edges are lightly browned.

Cool cookies on a wire rack. Drizzle with icing when cooled.

Icing Recipe: In a separate bowl, mix powdered sugar and 1 teaspoon of water. Add drops of water until icing is the consistency for drizzling.

Just before serving--using 2 spoons or a piping bag, fill the center of each cookie with a small spoonful of jam just before serving.