Step 1

Preheat oven to 350°F (180°C). Line baking sheets with parchment paper or silicone baking mats. Set aside.2

Step 2

. Combine the flour, baking soda, baking powder, cornstarch and salt in a medium sized bowl and set aside.

Step 3

. Cream the butter and brown sugar together in a large mixer bowl on medium speed until light in color and fluffy. You should be able to see the change in color and texture happen and know it’s ready.4.

Step 4

Add the egg and mix until well combined.5.

Step 5

Add the egg yolk and vanilla extract and mix until well combined.6.

Step 6

Add the dry ingredients and mix until the dough comes together and is combined. Do not over mix.7.

Step 7

Create 1 1/2 tablespoon sized balls of cookie dough. Gently roll into a ball, then roll each ball in the additional sugar to coat. Set the balls on the baking sheet.8.

Step 8

Bake cookies for 7-9 minutes. The cookies will spread and the centers will look soft, but should look done. Remove just before the edges begin to turn golden. Don’t over bake.R

Step 9

move from the oven and allow to cool on baking sheets for 4-5 minutes before transferring to a wire rack to cool completely.