Spicy Chocolate Chip–Hazelnut Cookies

In the early eighteenth century, a marriage took place in Turin, Italy, and the world has never been quite the same ever since. I’m talking about the sacred union of chocolate and hazelnuts, ground together into what is called gianduja. It was born out of economic necessity, when cocoa was expensive, and hazelnuts became a filler. Be forewarned: these cookies are maddeningly good.