Belgian chocolate and French cocoa from Callebaut and Valrhona are the secret behind these flourless, not-too-sweet brownies from Tatte Fine Cookies & Cakes, a Boston-area artisanal bakery famous for its European-style creations. The fudgy brownies are rich, moist and finely textured, not heavy. Our sampler includes four varieties: plain, walnut, pecan and hazelnut brownies, each carpeted with a topping of crunchy whole nuts. The treats arrive prettily packaged in a simple brown kraft paper box laced with tulle ribbon.