Once out of their shells, there’s the matter of roasting, because a rich-flavored hazelnut spread starts with a pile of sweet and fresh local hazelnuts roasted to the color of golden brown sugar.

Three things happen when you roast a hazelnut: It gets more flavorful, it blushes from the inside, and it takes on a pleasing crunch. So you definitely want to roast them in most cases. Another way to ...