Pre-heat your oven to 350°F.
In a large bowl, cream the butter and icing sugar together until smooth.
Stir in the almond extract and orange zest.
In a separate medium bowl, whisk together the flour, cardamom and salt.
Gradually add the flour mixture to your butter mixture, stirring until just combined.
Stir in the chopped walnuts.
Shape roughly tablespoon sized scoops of dough into crescent shapes.
Bake on a parchment lined tray for 10-12 minutes, until the bottom edges are slightly golden brown.
While the cookies are still warm from the oven, roll them in a bowl of icing sugar to coat them.
Transfer the sugar coated cookies to a wire rack to cool completely.