Just a handful of dried porcini mushrooms is enough to add a wonderfully rich, savoury flavour to this risotto. The cobnuts complement the earthiness of the porcini as well as adding a bit of crunch, contrasting with the creaminess of the risotto rice. Cobnuts are cultivated hazelnuts and can be bought fresh in their husks and shells in late summer and dried later on in the year. If you have difficulty in finding them, opt for hazelnuts instead. This risotto also works with pearl barley. Simply rinse and soak the barley for 1 hour, then cook for 45 minutes until the grain is tender and creamy.