In the bowl of your stand mixer, with the paddle attachment on, cream the softened butter with the powdered sugar, sea salt and ground cardamom for 2 minutes on medium low speed.
Mix in the egg white for about 1 minute until well incorporated.
Sprinkle the all-purpose flour, and continue to knead for another minute or until it is just combined. IMPORTANT: Do not over mix.
Place the dough in your Pastry Bag with the star tip on. Massage it for a minute in order to get the dough warmer. Then, pipe your cookies into an "S" shape.
BAKE!
Preheat oven to 350F/180C. Bake for 10 minutes (Every oven heats differently, monitor your butter cookies from 8min). It is ready when golden brown around the edge, the top staying white.
Once your Cardamom Shortbread Cookies are out of the oven, let them completely cool down. Then, slide them onto a serving plate. Serve and Enjoy! Bon Appétit!