Pre-heat the oven at 180°C for 15 mins.
Coat the pan with cooking oil. Line the pan-8 inch with parchment paper leaving an overhang on both sides of the pan. Set this aside.
In a medium mixing bowl, sift the flour, cocoa powder, baking powder, salt and powdered sugar until these are well combined.
Add chopped dark chocolate chunks and mix well. Set this aside for further use.
In a separate bowl mix together well pureed avocado and oil. Mix well until it becomes creamy.
Add hot water, mix well. Add vanilla essence and mix once.
Add the sieved dry ingredients in two portions. Add half of the flour mixture and mix gently.
At the end add the remaining flour mixture. Mix gently.
Pour the batter into the prepared pan and bake at 180°C for 25 to 30 minutes. When the top of the brownie is set and a toothpick inserted comes out clean with only few crumbs attached.
Remove from oven and allow the brownies to cool down completely before slicing into squares. After brownies have cooled completely, remove brownies from pan and slice them with serrated knife. Its normal for brownie to stick to knife since these are fudgy and gooey. Serve and relish the super moist gooey brownies.