• In a large bowl whisk together the first six dry ingredients and set aside.
• In the bowl of a stand mixer fitted with the whisk attachment, cream the butter, dark brown sugar, and orange zest at medium speed, until light and fluffy, for at least 4 minutes.
• Add the egg, molasses, and vanilla extract, scraping down the sides of the bowl. Mix until combined.
• Add the dry ingredients and mix until fully incorporated.
• Divide the dough into fourths. Form each quarter into a disc, and wrap with plastic. Chill the dough in the refrigerator for at least 2 hours.
• Preheat the oven to 350º F and line baking sheets with parchment paper.
• Remove one dough disk from the refrigerator and place it on a lightly floured surface. Sprinkle flour on top and, using a lightly floured rolling pin, roll the dough until it's 1/4-inch thick. Cut the dough using snowflake cookie cutters and transfer to a baking sheet.
• Re-roll the dough and repeat the process until you have used all the disks. You can always freeze the remaining dough and prepare it during the following week.
• Bake cookies for 8 to 10 minutes. Cool for a few minutes on the baking sheet before transferring to a wire rack.

Make the icing

• In a large bowl, whisk the icing ingredients together until smooth. The mixture should slowly drip, but should not be runny. If the mixture is too runny, add a little bit more powdered sugar. If it's too thick, add a little bit more water, one teaspoon at a time.
• Transfer to a piping bag with a tip and decorate your cookies when cooled completely.