Using an electric mixer on medium speed, beat 1 cup (2 sticks) unsalted butter, melted, cooled slightly, 1 cup (200 g) granulated sugar, and ½ cup (packed; 100 g) light brown sugar in a large bowl, stopping and scraping down sides as needed, until combined. vanilla bean paste or vanilla extract, add 2 large eggs, room temperature, and beat until mixture is pale yellow and starting to thicken and falls from beaters in a ribbon-like stream when lifted out of the bowl, about 3 minutes. We increased the amount of flour for a more controlled texture and spreading, added a weight measurement for the flour, clarified the instructions, and added vanilla extract and vanilla bean paste as alternatives to a whole vanilla bean.