Preheat the oven to 300°F.
In a stand mixer with the paddle attachment, beat together the butter, egg yolk, sugar, vanilla, cardamom and salt until incorporated.
Add in the flour (½ cup at a time) and turn the mixer on low to combine. The appearance of the mixture should go from flour-like crumbs to buttery crumbs.
When you reach this point, stop mixing and scrape down the sides of the bowl with a spatula. Turn the mixer back on and beat on low until the dough comes together and pulls away from the sides of the bowl.
Transfer the dough to a lightly floured surface and roll out the dough to about ¼ inch thick.
Using a medium sized cookie cutter, cut out the desired amount of cookies in any shape you like.
Transfer the cookies to a parchment lined cookie sheet, spacing each cookie ½ inch apart.
Sprinkle a pinch of cardamom sugar (which is 1 parts cardamom to 4 parts sugar) over the tops of each cookie.
Take a fork and carefully poke four incisions onto the tops of each cookie allowing the cookie to bake more evenly.
Bake for 50 minutes or until golden brown. Allow to cool completely before dusting with powdered sugar.