Preheat the oven to 340°F (170°C). Grease and line an 8x8inch (20x20 cm) square baking tin with baking paper, leaving some overhang for easy removal.
Melt the butter and dark chocolate together using a double boiler or microwave. Once smooth, stir in the powdered sugar, light brown sugar, vanilla and warm milk.
Whisk until the sugars are dissolved. Add the flour, cocoa powder, baking powder, and salt, then whisk until the batter is smooth and well combined.
Pour the batter into the prepared tin and bake for 25–30minutes, or until the brownies are set in the center and slightly risen. Let them cool completely in the tin.
In a saucepan, combine 270ml (1+⅛ cup) coconut milk, sugar, and cornstarch. Stir constantly over medium heat until the mixture comes to a boil and thickens.
Remove from heat and stir in vanilla extract, butter, and stir until combined.
Transfer into a clean bowl and stir in the shredded or desiccated coconut. Cover the with plastic wrap in contact with coconut cream.
Let the mixture cool in the fridge, then add the remaining 60ml (¼cup) coconut milk to loosen the consistency slightly. It should be soft and spreadable.
Once the brownie base is fully cooled, spread the coconut mixture evenly over the top.
In a separate bowl, using an electric whisk to whip cold whipping cream, vanilla and powdered sugar until stiff peaks form. Gently spread the whipped cream over the coconut layer.
Sprinkle with shredded coconut and chill in the fridge for at least 1 hour before slicing and serving.
