Put the stock in a pot and heat it. Wash the asparagus and cut off the tips, cut the rest of the stalks crosswise in 1 cm pieces.
Chop up onion, celery and garlic and saute them in olive oil in a large deep pan over slow heat for 10 minutes.
Then turn the heat to medium and add rice, and fry it while stirring for 2-3 minutes, add the wine and continue stirring until the wine evaporated. Add a ladle of the stock and cook over low/medium heat until the stock is absorbed by the rice.
Add the chopped asparagus reserving the tips to the rice, continue adding a ladle of the stock each time you see that the liquid got absorbed by the rice, keep stirring as doing so will bring out the creaminess in rice.
While your risotto is cooking, quickly cook the asparagus tips. They will take 5-7 minutes, so arrange for both asparagus and risotto be done at approximately the same time.
When all your stock is gone taste your rice to make sure it's cooked, if it's not add a ladleful of water.( Risotto is NOT rice pudding and shouldn't disintegrate in your mouth. Rice just like pasta should be cooked al dente- slightly firm to the bite.)
When the rice is the right texture remove it from the heat and stir freshly grated parmesan into it , then add butter, cover with the lid and walk away for 5 minutes.
Place a few asparagus spears on each plate.