Peel and dice the onion. Heat the olive oil in a pan and saute the onion until softened.
Add the rice and cook, stirring, for 1-2 minutes. Pour in the wine and simmer until evaporated.
Pour in the hot stock to just cover the rice.
Mix the saffron with a little stock and add to the rice.
Cook the rice over a low heat, stirring frequently, for 20 minutes until the rice is tender, adding more hot stock when needed. Season with salt and pepper.
While the rice is cooking, wash the asparagus, peel the lower third and blanch in boiling salted water for 6 minutes. Rinse under cold water and drain.
Plunge the cherry tomatoes into the boiling asparagus water for 30 seconds, cool in cold water, and peel off the skin.
Mix the parmesan into the risotto.
Cut the asparagus into small pieces and add to the risotto.
Stir in the cherry tomatoes and heat through.
Add the chopped parsley. Place the risotto on plates, sprinkle with parmesan and garnish with parsley.