In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, sugar, and vanilla together on medium high speed for 1 minute.
1 cup unsalted butter, ⅝ cup granulated sugar, ½ teaspoon pure vanilla extract
Add the flour, salt, and cinnamon. Beat together to incorporate.
2¼ cups all-purpose flour, 1 teaspoon kosher salt, 1 teaspoon ground cinnamon
Add the orange zest and mix well. The dough will be fairly hard at this point.
2 tablespoons orange zest
Remove the dough from the bowl, form into a ball, and wrap it in plastic wrap. Refrigerate the cookie dough for at least 1 hour.
Once chilled, unwrap the dough and place it onto a well-floured surface. Preheat the oven to 350°F. Line a baking sheet with parchment paper. Set aside.
Roll out the dough into a rough rectangle about ½-inch thick.
Use a 2-3-inch cookie or biscuit cutter to cut as many cookies from the rectangle of dough as possible. Use a smaller circle (like a piping tip) to cut a hole from the center of each cookie. Carefully transfer each cookie onto the prepared baking sheet, leaving 1 inch of space between each cookie.
Bake for 11 minutes. The cookies will still be soft.
Remove cookies from the oven and place onto a cooling rack to cool completely.
Continue rolling, cutting, and baking the cookies until all of the dough is used and all of the cookies are baked.
Once the cookies are completely cool, make the glaze and decorate the cookies. Place a piece of parchment paper on the counter. Set aside. Whisk the powdered sugar, milk, and corn syrup together in a small bowl until completely smooth.
1 cup powdered sugar, 1 tablespoon milk, 1 teaspoon corn syrup
Dip the top of each cookie into the glaze. Do not dip the entire cookie into the glaze. Once dipped, pull the cookie straight up out of the glaze and hold it there for several seconds to let any excess glaze drip off. Flip the cookie over so that the glaze is right side up and place onto the parchment paper. Decorate with sprinkles, holly leaves, and berries. Repeat for all cookies.
Sprinkles
Once cookies are decorated, let them set at room temperature for at least 1 hour to allow the glaze to harden.