Proving that everything sounds better in Italian, “nocciola” rightly implies dark depths of flavor. The hazelnut grows abundantly in the Piedmont Region, and became a cocoa substitute as Italy rebuilt after World War II. This explains why nocciola gelato has the smooth richness of chocolate, and why Nutella tastes like chocolate spread with some hazelnuts, when it’s really the other way around. This recipephany produces a classic, crunchy biscotti with a toastier, more mouthwatering flavor than the almond variety. Because chocolate is hazelnut’s soulmate, I used to throw in mini chocolate chips. But the chips smeared when I sliced the warm cookies for the second baking. I found that a thin coating of melted…