1/2 cup unsalted butter at room temperature
3/4 cup brown sugar light or dark brown sugar
1 large egg at room temperature
1 teaspoon pure vanilla extract
1 and ½ cup all-purpose flour sift then measure correctly (see post above) if you incorrectly measure the flour these cookies may be dry!
1/2 cup unsweetened dark cocoa powder like Hershey’s Special Dark (regular cocoa powder or Dutch-processed may be substituted, but have a slightly different taste)
1 teaspoon cornstarch
3/4 teaspoon baking soda
1/8 teaspoon salt optional
In the bowl of a stand mixer, combine butter and sugar. Mix with the paddle attachment on medium speed until the mixture is light and fluffy. About 3 minutes.
Add egg and vanilla and mix another 2 to 3 minutes.
Scrape down the sides of the bowl and add the remaining ingredients with the mixer on low just until the ingredients are combined about 1 to 2 minutes.
Cover and refrigerate the dough at least one hour.
Preheat oven to 350° F.
Scoop cookie dough onto a room temperature sheet pan lined with a Silpat Non-Stick Baking Mat or spray with a non-stick vegetable spray 2-inches apart. I used a 1.5-inch spring release scoop that holds just over 1 tablespoon of dough to scoop uniform cookies. Spray the bottom of a glass with non-stick spray and flatten cookies slightly.
Bake for 8 to 9 minutes or until the edges have set and the tops are just beginning to set. They will turn from being ‘shiny’ to be more ‘matte’. They will firm up as they cool so be careful not to overcook them.
Remove the cookies from the oven and allow to rest on the cookie sheet for 2 minutes. After 2 minutes remove with a thin spatula to a wire rack to cool completely.
Storage tips above.
I recommend you Calibrate your Oven at least once a year to ensure it’s baking at the correct temperature.