Spray the inside of a slow-cooker bowl. Add dates, bicarbonate of soda and boiling water and stir to combine. Stand for 5 mins, stirring occasionally, or until water is absorbed.
Add the flour, ½ cup (110g) of the sugar, milk, egg, melted butter and vanilla to the slow cooker. Stir to combine. Use a rubber spatula to clean the sides of the bowl.
Sprinkle remaining sugar over batter and top with chopped butter. Using the back of a spoon, carefully pour extra boiling water into the slow cooker. Cover with lid and cook on high for 1 hour 40 mins or until a crust forms and top springs back when pressed with finger.
Serve pudding with ice-cream.
