Start by preheating your oven to 350°F (175°C).
In a medium bowl, whisk together flour, cornstarch, baking soda, and salt.
In a large mixing bowl, cream together butter and sugar until light and fluffy.
Add egg and vanilla extract, mixing until well combined.
Gradually incorporate the dry ingredients into the wet ingredients, mixing on low speed.
Drop rounded balls of dough onto a baking sheet lined with parchment paper.
Bake the cookies for 10-12 minutes, until edges are lightly golden.
Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack.
