Cheesecake lovers fall into two camps, and in New York, only one camp matters. Italian cheesecake? Who needs it? Certainly none of the slab-happy customers at steakhouses, delis, and -- most famously -- Junior's, where the archetypically mile-high, cream-cheese-saturated New York variety is plied. But which is the best? We asked big cheese Steven Jenkins, who revolutionized cheese sales in Manhattan at places like Dean & De Luca and Fairway. His personal favorite is the graham-cracker-crusted, sour-cream-topped work of Mitchel London, Ed Koch's former chef and the owner of two gourmet takeout stores (22A East 65th Street, 737-2850; 542 Ninth Avenue, near 40th Street, 563-5969). London's version is tasty but demure; a proper New York–style cheesecake needs to be part dessert, part spectacle. So we nominate the strawberry-blonde cheesecake at Brooklyn Diner USA (212 West 57th Street; 581-8900), baked, like all the colossal cakes sold there, by pastry chef Donald Garcia. Its name comes, according to owner Shelly Fireman, "from a song in some James Cagney film, 'The Girl With the Strawberry-Blonde Hair,' or something like that. The recipe dates back to the twenties, when my aunts came from Europe and ran a hotel in the Catskills where I think Jack Dempsey used to train." The cake ultimately turned up on the menu at the fighter's own midtown restaurant. But Fireman's improvement on his aunts' formula, which involves jumbo strawberries and a pitcher of chocolate sauce, has no competition. "It was so obvious," he says. "Who doesn't like chocolate strawberries? It's easier to put the strawberries on the cake than dip all the strawberries in chocolate." Another divergence: the cream cheese comes from a farm in Vermont, not a factory in Philadelphia. "If I thought someone had a better cheesecake," says Fireman, "I'd steal it."