This mushroom risotto with a hit of Japanese miso is all about umami. What's that? The fifth "savoury" taste. The Italians get it from Parmesan and anchovies, and Asian cuisines from soy and miso. Mushrooms have it in spades, so get this satisfying vegetarian dinner started by pan-frying them, add garlic and spring onion, then stir in arborio rice.