Set your oven to 180°C (356°F). While fan-assisted heat is an option, I prefer static cooking with heat from below, as my oven tends to be unpredictable.

Weigh all your ingredients carefully before starting to ensure accuracy and ease during mixing.

In a large mixing bowl, combine the butter and chocolate, both cut into small pieces.

Melt them in a microwave (in 30-second intervals, stirring each time) or over a bain-marie (double boiler).

Once melted, mix the chocolate and butter until smooth and glossy.

Stir in a heaped tablespoon of Nutella for added creaminess.

Add the sugar to the chocolate mixture and whisk until fully combined.

Crack the eggs in one at a time, whisking thoroughly after each addition.

Sift together the flour, baking powder, cocoa powder, and a pinch of salt.

Gradually fold this mixture into the chocolate batter.

Butter and flour your mold, or line it with baking paper to prevent sticking.

Pour the batter into the prepared mold and use a knife to draw a small line down the center.

Place the mold in the oven. After 10 minutes, lower the temperature to 160°C (320°F) and trace the center line again.

Bake for an additional 30 minutes, then switch to fan-assisted heat for the final cooking phase to ensure an even bake.