Chop the onion and lightly fry in olive oil for 2 minutes. Add rice and lightly fry for another two minutes.
Add 1 dl bouillon and stir constantly, letting the risotto cook. Repeat until all bouillon is used and the rice is cooked; this takes some 20 minutes.
At the end add butter, parmesan, lemon peel and juice. Stir well until smooth.
Serve with grilled tomatos and basil leaves.