Cream Butter and Sugar: In a large mixing bowl, cream the softened butter and granulated sugar until light and fluffy.

Add Yolks and Vanilla: Add the 2 egg yolks and vanilla extract. Mix until fully incorporated.

Combine Dry Ingredients: In a separate bowl, whisk together flour and sea salt. Gradually add the dry mixture into the butter mixture and stir until a soft dough forms.

Chill the Dough: Divide dough in half, shape into discs, and wrap in plastic wrap. Chill in the refrigerator for at least 1 hour.

Roll and Cut: Preheat oven to 350°F (175°C). Roll out chilled dough on a lightly floured surface to ¼-inch thickness. Cut into rounds with a cookie cutter and place on a baking sheet lined with parchment.

Brush and Bake: Lightly brush tops with the remaining egg yolk. Bake for 12–15 minutes or until edges are just golden.

Cool and Serve: Transfer cookies to a wire rack to cool completely.