01 -
Whisk sugar, cocoa, cornstarch and salt in a medium saucepan, breaking up lumps.
02 -
Whisk in about 100 ml milk until completely smooth, then gradually whisk in the remaining milk.
03 -
Cook over medium heat, stirring constantly and scraping the corners, until the mixture thickens and begins to bubble. Reduce heat and cook at a gentle bubble for 1 minute while stirring.
04 -
Remove from heat. Add chopped chocolate, butter and vanilla, stirring until smooth and glossy. If needed, press through a fine sieve to remove any small lumps.
05 -
Divide between four heatproof dessert cups. Cool for 10 minutes, then cover the surface with food-safe wrap if you prefer to prevent a skin.
06 -
Refrigerate for at least two hours until chilled and softly set. Serve with a spoon; this is a creamy pudding rather than a firm unmolded dessert.
07 -
Keep covered in the refrigerator and use within three days. Do not leave the cups at room temperature for more than two hours.