Butter and line an 8x8 baking tin with parchment paper then set aside.

Place half the chocolate and all the butter in a large microwave-safe bowl and microwave in 30-second increments, until the chocolate has melted. Whisk together until smooth and shiny, being careful not to over-mix. Set aside to cool slightly.

To the chocolate, add the sugar, eggs, and flour. Whisk to combine then fold in the remaining half chocolate and hazelnut.

Transfer the mixture into the prepared tin then cover the brownies with a layer of tin foil, making sure it's sealed nice and tight.

Now head over to the stove top: Lay an upside-down plate in the bottom of a wide and deep saucepan and fill with water until it almost reaches the top of the plate. Important notes: You need the saucepan to be wider than the cake pan, and deep enough for the brownies to rise with the lid on.

Bring the water to a simmer over medium heat. Once simmering, careful place in the cake pan to sit on top of the plate. You don't want the cake pan to be sitting in water, it is to be just over it.

Steam for about 90 minutes. NOTE: It’s important to top up with hot water if you see it running low during the cooking process.

Once set but still a slight jiggle in the middle, wearing oven mitts carefully remove from pan. Set aside to cool completely in the pan.

Cut your brownies into your desired sized squares. Enjoy warm with vanilla ice cream.

Store at room temperate for up to 3-4 days. They also freeze really well for up to 8 weeks.