Line the base of a small pudding tin with baking paper and reserve an extra piece to cover the top.
Place the butter and sugar into Thermomix bowl and mix for 30 seconds, speed 2.
Scrape down the sides and mix for a further 20 seconds, speed 2.5.
Add the eggs and vanilla extract and mix for 8 seconds, speed 4.
Add the milk, self-raising flour and cocoa and mix for 12 seconds, speed 4 or until combined.
Spoon the mixture into the pudding tin and place the extra piece of baking paper over the top before putting on the lid.
In a clean bowl, add 1500 grams of water to Thermomix bowl and bring to the boil. You can use the kettle function on a TM6 or heat the water for 5 minutes, Varoma temperature, speed 1. Continue to heat until temperature reaches 100 degrees.
Place the pudding tin in the Varoma basket and cook for 60 minutes, Varoma, speed 3.
Check the water level at the 60 minute mark and add more water if required.
Cook for a further 20 minutes, Varoma, speed 3. Carefully check the pudding by placing a skewer into the centre to check if cooked. If still wet, cook for a further 15 minutes before carefully remove the pudding tin leaving to cool in tin for 10 minutes.
Carefully turn pudding onto a plate, before cutting into slices and serve with custard or ice cream.