1. Preheat oven to 350 degrees. Grease a 9 inch 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 dry ingredients to the egg mixture until well combined.
6. Pour the batter into the pan and spread evenly.
7. Bake for 30-35 minutes, or until a toothpick comes out with a few crumbs. Remove brownie from oven and allow to cool for about 10-15 minutes, then remove to cooling rack to finish cooling.
8. Once the brownie is cool, make the cheesecake. Beat cream cheese and sugar until smooth.
9. Add vanilla extract and beat until combined.
10. In a separate bowl, whip heavy whipping cream until it starts to thicken. Add the powdered sugar and whip until stiff peaks form.
11. Gently fold the whipped cream into the cream cheese mixture.