Preheat the oven to 350° F. Grease an 8x8 metal pan and set aside.

In a small bowl, whisk together the flour, baking powder, salt, and cornstarch and set aside.

Place the butter in a microwave-safe bowl, and microwave for 45 seconds, or until melted. Stir in the cocoa powder until smooth.

Place the semi-sweet chocolate chips in a separate microwave-safe bowl, and microwave for 30 seconds. Stir the chocolate, and then microwave in 15 second increments until melted, stirring in between until smooth.

Add the melted semi-sweet chocolate chips into the cocoa powder and butter mixture. Stir until smooth.

In a large bowl, add the room temperature eggs, vanilla extract, vegetable oil, and cane sugar. Using a hand mixer, mix on medium speed for about 3 minutes until creamy. Don't mix for less time, mixing for 3 minutes will help the sugar start to dissolve (it will still be a little bit grainy).

Add the chocolate and butter mixture to the egg mixture, and mix with a hand mixer on medium speed until the batter is an even color. Then add in the whisked dry ingredients, and mix by hand with a rubber spatula. Halfway through mixing, add the milk chocolate chips. Then continue to stir until there isn't any loose flour. Don't overmix!

Add the brownie batter to the greased pan, and smooth the top over with a rubber spatula. Bake for about 22-24 minutes, until the center is barely set. Let the brownies cool for at least 15 minutes, and enjoy!