In a food processor, combine pistachios and almonds. Pulse until they are finely ground, but be careful not to grind them too much, or they’ll turn into a nut butter! In a bowl, combine the ground nuts, powdered sugar, flour, cinnamon, and orange zest. Stir in the vanilla extract and egg whites until a crumbly dough forms*. Using your hands, knead until everything is mixed together and the dough forms. Flatten, and wrap in plastic wrap. Chill at least an hour, but you can make it up to 2 days in advance.

Preheat oven to 350* F (170* C). After the dough has chilled, roll it on a powdered-sugar surface until it is about 1/8 inch thick. Using a star-shaped cookie cutter, cut out about 28 cookies, re-rolling as necessary. I like to dip the cookie cutter in powdered sugar before cutting, because it prevents sticking. Line on a greased baking sheet. They can be pretty close together, because they don’t puff up much. Bake for about 8 minutes, or until the edges are very lightly browned. Let cool completely.

Alternatively, for airy cookies, you can whip the egg whites until stiff peaks form. Fold the dry mixture into the egg whites, add the vanilla, and finish the recipe as directed.

While the cookies are baking, combine the remaining powdered sugar with the orange juice, milk, and vanilla. I start with 1 Tbs. each of orange juice and milk and add more liquid to get my desired consistency of icing. After the cookies have cooled, dip each one in the glaze. Add sprinkles if desired! Let harden, and keep stored in tupperware.