Preheat oven to 175°C.
Lightly grease an 10x10 -inch baking pan.
Line with baking paper and set aside.
Combine melted butter, oil and sugars together in a medium-sized bowl. Whisk well to combine. Add the eggs and vanilla.
Add in cocoa powder, flour and salt until just combined.
Fold in chocolate chips.
Pour batter into prepared pan, smoothing the top out evenly, and top with salt, if preferred.
Bake for 30-35 minutes.
Allow to cool to room temperature before slicing into 16 brownies. They’ll set while they cool.