How to make it
Whisk together the dry ingredients, then add the yolk, sugar, vanilla and butter. You can use either a mixer or food processor.
Mix the dough just until combined, then move to a flat surface & gently form into a ball. Wrap in plastic and chill.
Form into crescent shapes and place on parchment paper lined cookie sheets.
Bake until lightly golden, let cool then dust with powdered sugar before serving.