In a large bowl, whisk together the melted unsalted butter, granulated white sugar, and light brown sugar until the mixture is smooth and fluffy.
Add the unsweetened cocoa powder, salt, espresso powder, vanilla extract, vegetable oil, and heavy cream. Whisk everything together and then microwave the mixture for 30 seconds until warm (not hot). Whisk again to dissolve the sugar and cocoa powder.
Once smooth, add the eggs and whisk vigorously until they are well combined. Beat the mixture for about a minute to help lighten the batter.
Now, add the all-purpose flour and mix until you achieve a thick batter consistency.
Fold in the chocolate chips into the batter. You can either mix them in or sprinkle them on top once the batter is in the pan.
Transfer the batter to a 9×9-inch tray lined with parchment paper. Use a rubber spatula to smooth the top.
Bake in a preheated oven at 350°F for approximately 30 to 35 minutes.
Once out of the oven, allow the brownies to cool for about 25 minutes until they are set. Then, cut them into individual pieces and enjoy every fudgy bite!