In a medium-sized bowl, using an electric mixer on medium speed, beat together the butter and powdered sugar until creamy, about 1 minute. Add the orange zest and orange juice, and then beat until combined.
Sprinkle the flour, cornstarch and pinch of salt on top of the dough. Beat until just combined.
Place the dough on a piece of wax or parchment paper, and, using your hands, roll the dough into a 12” round rope with a 1” diameter. Twist the ends closed and refrigerate for at least 30 minutes. (The dough can be frozen for up to 2 months).
Preheat the oven to 350 and line a cookie sheet with parchment paper.
Remove the dough from the fridge, and slice into 1” coins. Place the cookies on the baking sheet, sprinkle generously with the graduated sugar.
Bake the cookies for 13-14 minutes, until fragrant and the tops of the cookies are dry. The cookies should not brown.
Let the cookies cool on the baking sheet for 1 minute, and then move to cooling rack to cool completely.