The retailer's bakery category director Scott Clarke said the use of a familiar brand gave consumers reassurance about the quality of the product.
"I think consumers want to see a reason to believe in why they should spend £5 on a pudding," he said.
"Last year they had a great product but this year there's something else added to it."
The premium own-label pudding has been allowed to mature for six months in Courvoisier VS Cognac and Clarke said the £200,000 investment was already reaping rewards.
"Sales are flying. It is the bestselling pudding in our range with double-digit growth, and despite the new ingredient, we have kept the price the same."