If you have a sweet tooth and love the soothing chill of a scoop of ice cream, you might want to take over Robb Duncan’s job. As founder, recipe developer, gelato taster and business mogul extraordinaire, this young man can look over the past decade and smile with pleasure: He has married his soul mate, he has two young children, and he has opened and developed a fast-growing gelato business in the D.C. area. The name? Dolcezza, which translates as “Sweetness.”