"Pastry chef" seems an inadequate title for Mathew Rice, who masterminds the desserts at the Benton Park restaurant Niche and its new, adjacent bakeshop, Veruca. "Mastermind" works — though that too seems to miss something essential about Rice's baking. His desserts plug into someplace deep in the unconscious, where the simple pleasures of our childhood reside: tollhouse cookies, Hostess snack cakes, s'mores. Rice interprets each in a way that brings both a smile of recognition and the thrill of the new. Those s'mores, for instance, are toasted-marshmallow semifreddo with salted caramel and a graham cracker. Not that all of Rice's ideas are rooted in the past. Sometimes it's a combination of cleverness and convenience, like his slices of red velvet cake served to look like a small sandwich wrapped in wax paper. And sometimes it's working with something no one else does, like the South Asian dish kulfi, a dense frozen dessert so good it might supplant ice cream as your favorite summer treat.