1. Preheat the oven

Preheat the oven to 180°C. Generously grease a large baking tray with butter.

2. Melt the butter and chocolate

Place the butter and chopped chocolate in a heatproof bowl and melt until smooth. While still warm, stir in the brown sugar. Set aside to cool slightly.

3. Whip the eggs and sugar

In a large bowl, whisk the eggs, granulated sugar and vanilla on high speed for 5 to 7 minutes until pale, thick and at the ribbon stage.

4. Combine the mixtures

Gently fold the chocolate mixture into the whipped eggs. Add the rum if using and fold to combine.

5. Add the dry ingredients

Sift in the cocoa powder, flour and salt. Fold gently with a spatula until just combined. Do not overmix.

6. Bake the pudding

Pour the batter into the prepared tray and bake for 20 to 25 minutes. The top should be shiny and crackled, while the centre should still have a slight wobble.

7. Serve warm

Scoop into bowls and serve immediately with vanilla ice cream. The contrast of warm pudding and cold ice cream makes all the difference.