Preheat oven to 350.
Mix the butter and sugar in a bowl until it turns fluffy and light in color
Add egg yolks one at a time
Add in the vanilla and mix
Add the flour, salt and baking powder until dough is just coming together.
Make 1 1/2 tablespoon sized dough balls. Roll into the sugar and place on baking pan.
Use your thumb or a small spoon to make an indent in the cookie.
Spoon your choice of jelly, jam or preserves to fill.
Bake 10-15 minutes or just until the edges are slightly browning.
Allow to cool for 5-10 minutes. Enjoy!
