Chocolate Overload Brownies

Bahan-bahan (16 porsi)

• ½ cup (1 stick) unsalted butter, (melted)
• 2 tablespoons vegetable or canola oil
• 1⅓ cups granulated white sugar
• ⅔ cup unsweetened cocoa powder
• 2 large eggs
• 1 teaspoon vanilla extract
• 1 teaspoon instant espresso powder
• ½ teaspoon salt
• ½ cup all purpose flour
• 1 cup semi sweet or milk chocolate chips ((plus more, for topping))