Whisk together the dry ingredients in a medium bowl.
Cream butter and sugar on medium-high speed until light and fluffy, about 2 minutes.
Mix in egg and vanilla until fully combined.
Gradually add the dry mix and stir until the dough just comes together.
Divide dough into two discs, wrap in plastic, and chill for 1 hour.
Preheat oven to 350°F (175°C) and line baking sheets with parchment.
Roll dough to ¼-inch thickness, cut shapes, and place 1 inch apart on sheets.
Bake for 8–10 minutes until edges are just golden.
Let cookies rest on the pan for 5 minutes before transferring to a wire rack to cool completely.
Notes
Testing Note (prep): After chilling, the dough rolls without sticking and holds crisp edges.Testing Note (cooking): Rotating the baking sheet mid-bake ensures even browning in my older oven.Testing Note (storage): Layer cookies with parchment in an airtight container to maintain their crisp texture.