Heat the olive oil over medium heat in a small frying pan.
Add the onion, and season with salt and pepper. Cook for 5-7 minutes, or until softened.
Add the rice to the pan, and sauté for 1 minute.
Spray a 4-5 quart slow cooker with cooking spray.
Pour the rice and onion mixture into the slow cooker. Add the broth and cook on high for 1 ½ hours.
Bring a medium saucepan of water to a boil. Place asparagus in a steamer basket, and steam until bright green and crisp tender, about 3-5 minutes.
Stir the parmesan and asparagus into the risotto. Garnish with parsley.