Step 1Heat the oven to 375 degrees. Using an electric mixer, cream the butter until smooth. Add the sugar and beat for one minute. Add the vanilla extract and egg yolks and beat an additional minute.
Step 2Sift together the flour and salt. Spoon the flour mixture into the butter mixture and add the cardamom. Beat on low speed, then increase to medium and mix until the batter is combined.
Step 3Spoon the dough into a cookie press and press out onto ungreased baking sheets. In a small bowl, combine the sparkling sugar and the pistachio nuts, then sprinkle some on each cookie.
Step 4Bake just until the edges of the cookies start to turn a pale golden color, about 8 to 10 minutes. Remove the cookies from the baking sheet immediately and cool on a wire rack. The cookies will firm up as they cool. When they are completely cool, store in an airtight container. They may be kept frozen up to two months.