INGREDIENTS
•
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
•
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