Preheat oven to 350ºF. Arrange the oven racks so they divide the oven into thirds. Line two baking sheets with parchment. Using an electric mixer on medium-high speed beat the butter until light and fluffy, about 2 minutes. Add the liqueur, vanilla, sugar, and zest, and continue beating for 2 minutes. Add the salt, cinnamon, anise seed, and nuts, and beat for 30 seconds. Beat in the flour on low speed until it is thoroughly mixed into the dough. Scrape the bottom and sides of the bowl and give the dough a few stirs to be sure it is completely mixed. Shape the dough into 1" balls and place them one inch apart on the prepared baking sheets. Bake about 20-22 minutes, reversing the pans halfway through the baking time, until the cookies are golden brown and firm but not hard. Cool the cookies on the baking pans for 5 minutes, then roll them in the confectioners sugar. Let them cool completely, then roll them in the sugar again. Store the cookies in an airtight container.