Preheat oven to 300°F. (Yes, that’s 300 – not a typo.)

Cream the butter and powdered sugar in the bowl of a stand mixer with the paddle attachment or hand mixer with a very large bowl. Mix it until it’s nice and light and fluffy and smooth, about 3-5 minutes, scraping the bottom and sides of the bowl during mixing. (3 minutes for a stand mixer, 5 minutes using a hand mixer.)

Add the flour, cornstarch, salt and vanilla and mix until smooth, scraping the sides and bottom of the bowl as needed.

Scoop 1 tablespoon size balls of cookie dough and roll them between your palms to form a ball. Place on cookie sheet. These don’t spread so you don’t have to space them more than 1-2” apart.

Lightly flour a fork and use the tines to press down the cookies. Top with nonpareils in your desired color.

Bake for about 20-22 minutes or until the bottoms are lightly browned. Cool slightly before removing from pans.