1. Prepare the Crust:

1. Preheat oven to 325°F (165°C) and line baking sheets with parchment paper.
2. In a large bowl, beat the softened butter with an electric mixer until light and fluffy, about 3-4 minutes.
3. Gradually add the powdered sugar and continue beating until well combined and smooth.
4. Mix in the vanilla extract, then add the flour, cornstarch, and salt, mixing on low speed just until the dough comes together.
5. Drop dough by rounded teaspoonfuls onto the prepared baking sheets, or pipe using a star tip for a decorative look.
6. Sprinkle the tops of the cookies generously with holiday sprinkles.
7. Bake for 15-18 minutes, or until the edges are just lightly golden. Do not overbake.
8. Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.