– 1 cup unsalted butter (2 sticks), melted – 2 cups granulated sugar – 4 large eggs, at room temperature – 2 teaspoons vanilla extract – 1 cup all-reason flour – 3/four cup unsweetened cocoa powder – 1/2 of teaspoon salt – 1 cup semisweet chocolate chips or chopped chocolate (optional, for delivered richness)