01 -
In a large bowl, beat the softened butter, brown sugar, and granulated sugar for about 2 minutes, until lighter and creamy.
02 -
Beat in the egg yolk and vanilla extract until smooth. Scrape down the sides and bottom of the bowl.
03 -
In a separate bowl, whisk together the flour, cornstarch, cinnamon, baking soda, and salt. Add to the butter mixture and mix on low just until combined.
04 -
Cover the dough and chill for 30 minutes. Heat the oven to 350 F and line two baking sheets with parchment paper.
05 -
Stir the coating ingredients together in a small bowl. Scoop the dough into 1 1/2 tablespoon portions, roll into balls, and coat each ball in cinnamon sugar.
06 -
Arrange dough balls 2 inches apart. Bake for 10-12 minutes, until the edges are set and the centers still look soft and puffy.
07 -
Let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack. They will finish setting as they cool.