Tinned sponge pudding by Heinz.
This would have been boiled in a saucepan for 40 minutes to heat it up. People would often eat it with hot custard.
Other Heinz puddings to come in tin cans included Spotted Dick but they are better known for their tomato ketchup, salad cream and baked beans. Their tagline from the 1960s “Beanz Meanz Heinz” is thought to be one of the best known advertising slogans in the UK.