Adapted from “A Baker’s Odyssey,” by Greg Patent This is a spectacular 3-layer walnut torte, about 4 inches tall, filled and frosted with mocha whipped cream. The tender, not too sweet, cake layers--given their structure and flavor from ground walnuts and fresh bread crumbs--are leavened only by beaten eggs. Make this for a special celebration, or whenever you’re feeling especially festive. Because the cake contains fresh bread crumbs, substitute matzoh meal during Passover. The walnuts for this cake must be finely ground. The preferred way of grinding the nuts is with a manual nut grinder clamped to the side of the table. When ground this way, the nuts are fluffy and powdery and mix into the batter easily. If you have a hand-held Mouli grater, it will do a fine job of grinding the nuts. When grinding walnuts with a food processor, you have to be careful that the nuts don’t take on a pasty texture. To prevent that from happening, process the nuts in batches with the fresh bread crumbs. Walnuts must be ground at room temperature. Except for storage, do not refrigerate or freeze the nuts.