Special equipment: a large and a small star cookie cutter; 20 oven-safe lollipop sticks
Preheat the oven to 302 degrees F/150 degrees C. Line 3 baking sheets with parchment.
Place the flour in a bowl or on top of a clean work surface. Add the butter and rub it through the flour until it resembles fine breadcrumbs. Make a well in the center and add the sugar, eggs and vanilla if using. Gently mix to form a dough. Wrap the dough in plastic wrap and refrigerate for 30 minutes.
Dust a work surface with flour and roll the dough to about 1 centimeter (1/2 inch) thickness. Use a large star cutter to cut out stars. Place them on the prepared baking sheets. Use a smaller star cutter to cut the middle out of the large stars. Push an oven-safe lollipop stick through the bottom of a star. Repeat with the remaining stars. Fill the middles of the stars with crushed rock candy. Bake until the edges are golden brown, about 25 minutes. Allow to cool on the baking sheet until the candy has set hard.
Brush the cookies with edible silver luster dust for sparkle and shimmer.