Bring a pot of water to a boil with a large pinch of salt. Add the asparagus and boil for about 6 minutes or until just tender. Drain, reserving the cooking liquid and leave the asparagus to cool. Cut the aspargus into small pieces, leaving the heads intact. If any stalks are very tough, discard them. Reheat the cooking liquid.
Fry the shallots in half the butter for about 5 minutes until soft and transparent. Add all the rice all at once. Stir until heated through. Season with salt and pepper, then begin adding the hot asparagus stock, stirring continuously. Add a ladleful at a time and wait for the rice to absorb it before adding any more liquid. This will take about 20 minutes. Add the asparagus to heat through at the end of cooking. When the risotto is creamy and velvety but the rice is firm to the bite, stir in the cheese and parsley and season to taste with the pepper. Remove from the heat, cover and leave to stand for about 3 minutes. Transfer to a warmed serving platter and serve at once.