STEP 1

Preheat oven to 180°C (160°C fan). Line a 20cm square baking tin with parchment paper.

STEP 2

Melt the butter and dark chocolate together in a heatproof bowl over a pan of simmering water, stirring until smooth. Set aside to cool slightly.

STEP 3

In a separate bowl, whisk the eggs and sugar together until pale and slightly thickened.

STEP 4

Pour the melted chocolate mixture into the egg mixture and fold gently to combine.

STEP 5

Sift in the flour, cocoa powder, and salt. Fold until just combined — don't overmix.

STEP 6

Pour half the batter into the tin. Dollop spoonfuls of Hazelnut Mellori over the top, then cover with the remaining batter. Swirl gently with a knife.

STEP 7

Bake for 22–25 minutes, until the edges are set but the centre still has a slight wobble.

STEP 8

Cool in the tin for 15 minutes before slicing. Serve warm for that molten centre.