Now, as grown-ups, we are lucky to be living through an American ice cream renaissance. Places like Morgenstern's in New York City have a charming, old-school feel, complete with servers in paper hats. But the crumbly topping they offer of pleasantly bitter coffee-honeycomb crunch is far from traditional—it's complex, intriguing, and delicious in ways a sugar bomb could never be. At Salt & Straw in Portland, old-style hot fudge is merely a jumping-off point for myriad variations, which include ingredients like toasted white chocolate, sesame, and rich, fruity olive oil. At this new wave of ice cream shops, the focus isn't on enormity, but on pioneering flavor. Here are sundaes that begin with the most luxurious mail-order ice creams around, and end with deluxe toppings from some of our favorite American creameries.