Parmesan risotto (Marcella Hazan)

Dilute one cup of canned beef broth with four cups of water in a saucepan and bring to a slow, steady simmer.

Chop the onion very finely; grate about half a cup of Parmesan.

Keep the arborio rice raw and unwashed.

In a broad sturdy pot over medium-high heat, cook the chopped onion in butter and oil until translucent.

Add the rice and stir quickly until every grain is coated.

Add half a cup of simmering broth; stir constantly, wiping the bottom of the pot clean, until no liquid remains, then add another half cup. Keep the heat lively.

Taste after 20 minutes of cooking: it should be firm to the bite and moist and runny.

Off the heat, stir in all the grated Parmesan and the remaining butter, and a pinch of salt.

Serve promptly; shave truffle over and grate a little more Parmesan on top.