Sift together the flour, baking soda, corn starch, spices, and salt in a large bowl. Set aside.
In the bowl of a large stand mixer, cream together the butter, brown sugar, and orange zest for 2-3 minutes until fluffy and well-mixed. Add the eggs one at a time, beating well after each addition, then add the molasses and vanilla. Mix on low speed until the molasses is incorporated.
Turn the mixer off and add the dry ingredients. Turn the mixer to low and mix slowly until just a few streaks of flour remain. Stop the mixer and finish stirring in the flour with a spatula, scraping the bottom and sides of the bowl to make sure that everything is well-mixed.
Divide the dough into thirds and roll each third out between two pieces of parchment paper, so that the dough is ¼-inch thick. Refrigerate the rolled dough for 45-60 minutes, until firm.
Cut out two of each size of star, except for the smallest size—cut out three of those. Place the cut-out cookies on baking sheets covered with parchment, Try to keep similar sizes of stars on the same sheet, so they bake evenly, and space the cookie about 2 inches apart. Preheat the oven to 350 F and refrigerate the trays while the oven preheats, so that the cookies are chilled going into the oven—this will help them hold their shape and not spread too much. Re-roll the scraps of dough if necessary, until you’ve cut out all of the stars you need.
Bake the smaller stars for 7-10 minutes and the larger stars for 10-12 minutes, until light brown, slightly puffed, and no longer shiny in the center. Transfer the cookies to a wire rack to cool completely. Cookies can be made in advance and kept in an airtight container at room temperature for 3 days, or for 3-4 weeks in the freezer.
To Make the Glaze and Decorate:
Combine the powdered sugar, milk, corn syrup, and ½ tsp almond extract in the bowl of a large stand mixer fitted with a paddle attachment. Mix on low speed until the sugar is moistened, then raise the speed to medium-low and mix until you have a fluid glaze with the consistency of liquid glue. Taste it, and add more almond extract if desired. If your glaze is very thick, add a bit more milk, and if it seems too thin, add more powdered sugar.
Spread parchment out over your work surface, and place wire drying racks over the parchment. Place a small wire rack over the bowl of glaze, and put a cookie on top of the rack. Dollop some glaze on the cookie, and use a small spatula to spread it all over, covering the top and sides of the cookie completely and letting the excess glaze drip back into the bowl.
Once the cookie is covered, transfer it to the wire racks over the parchment to set, and repeat with the remaining star cookies. Let them sit at room temperature for 1-2 hours, until the glaze is hard and set. Press a layer of cling wrap on top of the excess glaze in the bowl so it doesn’t harden and dry out.
When the cookies are set, stir a few more spoonfuls of powdered sugar into the bowl of glaze, so it’s thick enough to pipe on the sides of the cookies and not drip down. Fill a disposable piping bag or a gallon-sized plastic zip-top bag with the thickened glaze, and put your sparkling sugar in two shallow pie tins.
Pipe a thin line of glaze along the side of one of the stars, then press the sparkling sugar into the glaze. Set it back on the wire rack to dry, and repeat with the remaining stars and sprinkles. Alternate colors of sprinkles so that for each pair of stars, 1 is gold and 1 is white. For the smallest size, after you do 2 of the stars with gold and white sprinkles along the edge, spread a thin layer of glaze all over the remaining smallest star and cover it with gold sprinkles.
Place the largest star on your serving platter, and pipe a quarter-sized dollop of glaze in the center. Top it with its mate, the other largest star, but offset the star so that the points go in a different direction. Add another dollop of glaze and top it with the second-largest star, then repeat with the remaining stars. When you get to the top and have only the gold sprinkle-covered star remaining, place a dollop of glaze on the top star and stick a toothpick into the stack of cookies. Set the gold star on top, in the glaze, leaning back against the toothpick. Let the cookie tree set for at least 15 minutes before you move it. For the freshest taste and texture, serve within 2-3 days.