Heat oven to 350 degrees.

Cream the butter, sugar, salt, and vanilla in a mixer.

Slowly add the flour and mix well.

Roll the dough into small balls and place on a parchment lined cookie sheet.

Press your finger, gently, in the middle of the ball to flatten and leave an indentation in the middle, to be a "pocket" for the jam.

Fill each pocket with a dollop of jam. Remember, the cookies will spread a bit, so extra jam is good, so that it will spread too :)

Bake for about 15 - 18 minutes, or until you see a slight hint of golden color on the cookie. Remove from oven and let cool.

Meanwhile, mix the powdered sugar and lemon juice to make the icing.

Using a pastry bag, squiggle the frosting across the tops of the cookies.