Cream the Butter and Sugar: In a large mixing bowl, beat together 1 cup of softened unsalted butter and 3/4 cup of granulated sugar until smooth and creamy.

Add Flavor and Egg Yolk: Add 1 teaspoon of pure vanilla extract and 1 large egg yolk to the mixture, mixing until fully incorporated.

Incorporate the Flour: Gradually sift in 2 cups of all-purpose flour and 1/4 teaspoon of salt, stirring until the dough just comes together.

Shape and Chill the Dough: Transfer the dough onto a floured surface, shape into a log, and refrigerate for at least 2 hours.

Prepare for Baking: Preheat your oven to 325°F (160°C) and line two baking sheets with parchment paper.

Slice the Dough: Unwrap the chilled dough and slice into 1/8-inch thick rounds, placing them 1 inch apart on the baking sheets.

Bake the Cookies: Bake for 16-18 minutes until the edges are lightly golden while the centers remain pale.

Cool and Serve: Allow cookies to cool on the baking sheets for 5 minutes, then transfer to a wire rack to cool completely.