Preheat the oven to 325°F. Spray a 9X4 loaf pan with baking nonstick spray. Line the bottom and 2 sides of the pan with parchment paper. Spray again.
Using a mixer and a large bowl, add the sugar and eggs. Beat on high speed for 5 minutes. Melt the butter while it beats. Let it cool.
1 cup White granulated sugar, 2 Large eggs, ¼ cup Unsalted butter
Add in the melted butter, oil, and vanilla to batter. Mix in on low speed. Sift the flour and cocoa powder and add to the bowl. Add in the cornstarch and salt. Mix on low.
¼ cup Oil, 1 teaspoon Pure vanilla extract, ½ cup All-purpose flour, ½ cup Dutch process cocoa powder, ½ tablespoon Cornstarch, ¼ teaspoon Salt
Add in the chocolate chips. Take off the mixer and use a rubber spatula to fold the chips in.
¼ cup Semi-sweet chocolate chips, ¼ cup Milk chocolate chips
Pour the batter into the loaf pan. Spread until smooth.
Bake for 45-50 minutes. Bake until slightly underbaked in the middle. It will continue to bake as it cools.
Cool the brownies in the pan on a wire rack until completely cool. Take the brownies out of the pan and cut into 8.