Step 1

Preheat the oven to 350°F. Line a baking sheet with parchment paper; set aside.

Step 2

In a medium bowl combine the flour and salt together.

Step 3

In the bowl of your mixer add the butter and brown sugar then mix until light and fluffy for a couple minutes. Add the egg yolk, vanilla extract and continue mixing until combined. Add the flour mixture and mix until well incorporated.

Step 4

In a small bowl beat the egg white with a fork. In another shallow bowl place the finely chopped walnut.

Step 5

Shape the dough into 1 inch balls. It might be easier to use a small cookie scoop to ensure that each ball is of equal size. Roll each ball in the egg white, then roll them in walnuts making sure to coat them well. Place the balls on the prepared cookie sheet and press a deep indentation in the center of each ball with your thumb. I find it easier to use a washed and dried wine cork.

Step 6

Transfer the baking sheet to the oven and bake for 8 minutes. Now carefully fill each cookie with about ¼ teaspoon of jam per cookie. Transfer the cookie sheet back to the oven and bake for another 8 minutes or until the edges are lightly browned.

Step 7

Place cookies on wire racks to cool completely.