Using butter instead of oil has several benefits. For one, it gives your brownies a more authentic and traditional flavor. It's also a great way to add more flavor to your brownies, since butter has a rich and creamy taste. Plus, who doesn't love the smell of melted butter wafting from the oven?
Another benefit of using butter is that it can help to balance out the bitterness of the cocoa powder. This is especially important if you're using a high-quality cocoa powder that has a strong and bitter flavor. By using butter, you can create a rich and well-balanced flavor profile that will impress your friends and family.
Butter vs. Oil in Baking: Which is Better? | Handle the Heat