Instructions:
- Cream Butter and Sugar: In the mixer bowl, beat the room-temperature butter until smooth. Gradually add the granulated sugar and beat on medium speed until the mixture is pale, light, and fluffy (about 3-4 minutes).
- Incorporate Wet Ingredients: Beat in the egg yolks one at a time until fully incorporated. Mix in the vanilla extract. Scrape down the sides of the bowl.
- Whisk Dry Ingredients: In a separate bowl, whisk together the flour, cornstarch, and salt thoroughly to ensure even distribution.
- Combine Dough: Gradually add the dry mixture to the wet ingredients on low speed, mixing just until a soft, cohesive dough forms. Stop mixing as soon as the last streaks of flour disappear to avoid over-mixing.
- Chill the Dough: Divide the dough into two equal discs, wrap each tightly in plastic wrap, and refrigerate for a minimum of 60 minutes.
- Preheat and Prep: Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper or silicone mats.
- Shape the Cookies: Roll the chilled dough out to about 1/4 inch (6mm) thickness on a lightly floured surface. Use cookie cutters or cut into even shapes, and place on the prepared sheets, leaving 1 inch between them.
- Bake: Bake for 10–12 minutes. Cookies are done when the edges are just beginning to turn a very pale gold.
- Cool: Let the cookies rest on the baking sheet for 5 minutes before carefully transferring them to a wire rack to cool completely.
- Finish (Optional): Once fully cool, dust generously with confectioners’ sugar.