Cut off the bottom tough inch or so of the asparagus and discard. Cut off the top inch of all the spears and set aside. Slice the asparagus stalks into little disks about 1/4 inch thick.
Heat half the butter in a saucepan over medium-low heat. Sauté the green onions, asparagus, salt and crushed red pepper until the asparagus is tender. Add the rice and sauté for about four minutes, stirring more or less constantly.
Dissolve the salt in the stock, and add the stock, one cup at a time, stirring until the rice has absorbed almost all the liquid. The rice is done when there is no crunch left in the center, and when starch from stirring the rice grains forms a moderate amount of what seems like a creamy sauce. But don't allow it to get mushy. Texture is everything in risotto. You'll know it's ready if you pay close attention throughout the cooking. At that point, remove it from the stove and cover the pot.
Bring a small saucepan of water to a simmer, and cook the asparagus tips for three minutes, or until tender. (Even better: steam them, if you have a steamer.) Drain and stir the tips into the rice, along with the Parmigiano, basil, mint, parsley, and the rest of the butter.