Preheat oven to 160 degrees celcius. Grease a large oven baking dish and set aside (minimum of 6 cup capacity).
Place butter into a clean Thermomix bowl and melt for 2 minutes, 100 degrees, Speed 1. Allow to cool slightly.
Add the milk, vanilla extract and egg and mix for 20 seconds, Speed 4.
Add the self-raising flour, cocoa powder and caster sugar and mix for 10 seconds, Speed 4. Scrape down the sides of the bowl and mix for a further 10 seconds or until smooth.
Pour the mixture into the prepared dish.
Boil the water and set aside.
Sift the extra cocoa powder over the pudding mixture then sprinkle over the extra caster sugar. Carefully pour over the boiling water.
Bake for 30 minutes or until firm on the top. Allow to cool slightly, then dust with icing sugar or serve with ice-cream, custard or cream.
Notes
RECIPE NOTES & TIPS
Pour the boiling water over the pudding just before cooking.
Use a large spoon (turned over) to pour the boiling water over the pudding so that it doesn't disturb the pudding batter.
Once baked, serve immediately (the sauce will start to soak into the pudding once cooled).
Do NOT overcook the pudding. The cake layer should be just cooked through and wobbly, while the sauce underneath will be runny.
Serve warm with custard, cream or ice-cream.
This recipe can be stored in an airtight container for up to 3 days or freeze for up to 3 months. Please note: once cooled, the sauce will soak into the pudding.