Preheat the oven to 350°F. Line a 9×13'' pan with parchment paper and butter or grease any exposed edges.

In a large microwave-safe bowl, melt the butter and chocolate chips together in 30-second increments, stirring between rounds, until smooth.

Next, whisk in the cocoa powder and oil until you have a smooth, silky mixture.

While the mixture is still warm, stir in the sugar until combined. Then, add the eggs and vanilla and whisk until thoroughly combined.

Lastly, fold in the flour, salt, and any mix-ins. Spread the batter evenly in the prepared pan.

Bake the brownies for 30-35 minutes, until the top is set and an inserted toothpick has a few moist crumbs.

Let the brownies cool completely. Using the edges of the parchment paper, remove the brownies from the pan and cut them into either 16 large or 24 small bars. Dust with powdered sugar, if desired. Enjoy!