In large mixing bowl, cut the butter into the flour until it starts to come together as crumbs.

Stir in the mashed egg yolks and confectioners sugar, mixing well.

Gather the dough into a ball and wrap in plastic wrap. Refrigerate for at least one hour or longer.

Preheat oven to 350 degrees.

Take walnut-sized pieces of dough and roll into a rope. Form into a pretzel shape and place on a parchment-lined baking sheet.

Brush the cookies with the beaten egg and sprinkle with colored sugar or sprinkles.

Bake for 12-14 minutes or until golden brown.

Cool for 10 minutes on a cookie rack.