– butter unsalted, melted – granulated sugar – brown sugar packed – vanilla – eggs room temp – flour
Beat melted butter, sugars, and vanilla in a large bowl using an electric mixer or stand mixer. Add eggs, one at a time, continuing to mix until well incorporated.
In a separate mixing bowl, whisk together flour, cocoa powder, baking powder, cornstarch, and salt. Gradually add the flour mixture to your batter, mixing on low speed.