Steam the asparagus briefly, drain, and set aside. In a medium saucepan, bring 3 cups of lightly salted water to a boil. Add the scallops to the water and cook (poach) until white and firm. Drain, set aside, and keep warm. In a separate saucepan, heat the broth. In a skillet, melt the butter over medium heat. Add the onion and saute until soft. Add the rice to the onion, reduce the heat, and stir for 3 minutes. Add the hot broth, ½ cup at a time, stirring until the liquid is absorbed before adding more. Continue cooking and stirring for about 20 minutes, or until the rice is tender. Remove the rice from the heat. Add the cream, Parmesan, scallops, and asparagus. Season with salt and pepper.