1. Preheat oven to 350 degrees. Grease a 9×9 square baking pan, or line it with parchment paper.
2. Mix together the oil, sugar and vanilla extract.
3. Add eggs and mix until well combined.
4. Combine flour, cocoa, baking powder and salt.
5. Slowly add to the egg mixture until well combined.
6. Pour the batter into the pan and spread evenly.
7. Bake for 25-30 minutes, or until a toothpick comes out with a few crumbs.