n a large bowl of a stand mixer, combine the butter, sugar, salt on low speed until the butter combines with the sugar but isn't completely smooth, 1-2 minutes. Add the flour, cardamom and zest, mixing on low speed until the dough has just pulled together, about 3 minutes.
On a lightly floured surface, roll the dough to about 1/4-inch thickness. Cut the dough into bars, squares or shapes using cookie cutters. Cut shapes as close together as possible. Press scraps together and roll again for more cookies. If dough becomes too warm, refrigerate briefly.
Arrange cookies on a parchment lined sheet and refrigerate until chilled, at least 20 minutes. While chilling preheat oven to 300 degrees.
Bake cookies on parchment lined sheets for about 30 minutes (rotating pans halfway through baking) until tops are a pale golden color. If cookies are down before 30 minutes adjust temperature to 275 degrees; if longer than 30 minutes adjust to 325 degrees for remaining batches