Preheat the oven to 180°C (top and bottom heat) or 170°C (fan-assisted).

Line a baking pan with parchment paper, or grease it with butter and dust lightly with flour.

In a saucepan, gently heat the butter together with the chopped chocolate.

Warm the mixture, stirring from time to time, until smooth and fully melted.

Remove the saucepan from the heat and immediately add the sugar, stirring with a spoon until combined.

Add the eggs one at a time, mixing vigorously after each addition until the batter is glossy and smooth.

Finally, add the flour and mix just until incorporated.

Pour the batter into the prepared pan and bake for about 30 minutes.

As soon as the brownie comes out of the oven, poke holes all over the surface with a fork or skewer and pour over the chocolate glaze.

While the brownies are baking, prepare the glaze. Heat the heavy cream in a small saucepan.

Once hot, add the chocolate and coffee (if using).

Stir until the chocolate is completely melted and the glaze is smooth and silky.

Pour the glaze evenly over the top of the brownies.

Spoon the Nutella or another chocolate-hazelnut spread into a small bowl and gently warm it up (for example, in the microwave) until it becomes smooth and pourable.

Transfer the kadayif pastry to a large bowl, add the warmed Nutella, and mix thoroughly until every strand is well coated.

Spread the kadayif mixture over the brownies and smooth the top into an even layer.