Preheat oven to 175°C

In a sauce pan, melt the butter & add in the choco, cocoa powder & vanilla. Stir until the choco melted. Take off the heat & transfer to the mixing bowl& let cool

Once the butter mixture has cool slightly, beat eggs & sugar for 5 minutes. Once the butter mixture is luke warm, add the egg mixture & stir until combine

Mix in the flour & sal until just combined. Don't overmix!! Add in the additional choco at the stage if you want extra decadent brownie

Pour in to the prepared tin & bake for 35 minutes or longer for less fudgy brownie