Trendhunter.com reported on the world's most expensive ice cream sundae, the $1,000 Grand Opulence Sundae from Serendipity of New York City. Somebody should call Guinness to let them know there is a new kid on the block - Three Twins Ice Cream's "World's Most Expensive Ice Cream Sundae". So how much is it? - $3,333.33. The sundae is made with three rare dessert wines (see image) As a member of 1% For The Planet, an organization whose members give a portion of their profits to environmental groups, one-third of the purchase price will be donated to a local land trust.