How to Make It
In a large saucepan, bring the chicken broth to a boil over high heat. Cover and keep hot over low heat.
In a heavy 6-quart pot or casserole, melt 2 tablespoons of the butter over moderate heat. Add the onion and cook, stirring occasionally, until softened, about 6 minutes. Crumble in the saffron threads and cook for 1 minute, stirring. Add the rice and stir to coat thoroughly with butter, about 2 minutes. Add the wine and cook over moderately high heat, stirring, until evaporated. Add enough hot stock to cover the rice (about 1 1/2 cups) and bring to a boil, stirring. Reduce the heat to moderate. Cook, stirring the rice constantly, until the stock has been absorbed. Continue adding the stock, 1 1/2 cups at a time, and stirring until it is absorbed before adding more; the risotto is done when the rice is just tender and the liquid is thick, about 25 minutes total.
Remove the risotto from the heat and stir in the remaining 2 tablespoons of butter and the cheese. Season the risotto with salt and pepper and serve.