Preheat the oven to 350F then line an 8x8 inch baking pan with parchment paper and set aside.
In a microwave-safe bowl melt the butter, oil, both sugars, and cocoa powder together in 30-second intervals mixing in between every time. Once fully melted microwave for another 1 minute and stir vigorously to allow the sugar to melt fully and emulsify with the fats.
⅔ cup butter, 2 tablespoon vegetable oil, ¾ cup granulated sugar, ¼ cup brown sugar, ⅔ cup cocoa powder
Whisk in the eggs one at a time then add in the vanilla. You want the batter to pull from the bowl a little bit.
2 egg, 1 teaspoon vanilla extract
Add in the flour, and the salt and fold just until combined. Fold in the chocolate chips.
½ teaspoon salt, ⅔ cup all purpose flour, ½ cup semi-sweet chocolate chips
Pour the batter into the parchment paper-lined 8x8-inch baking pan and spread evenly. Bake in the preheated oven for 30 minutes.
Allow the brownies to cool down fully on a wire rack before slicing into them for the perfect square crinkle top slice every time.