Add the broth to a medium saucepan and bring to a simmer over medium heat. Cover and reduce the heat to low.
In a large heavy saucepan or Dutch oven, melt the butter over medium heat. Add the sausage and saute, breaking it up with a wooden spoon as it cooks, until golden brown and cooked through, about 5 minutes. Add the onion, pepper and mushrooms, and saute until tender, stirring occasionally and scraping up the browned bits on the bottom of the pan, about 8 minutes. Season with salt and pepper.
Add the rice and stir to coat. Add the wine and simmer until the wine has almost completely evaporated, about 1 minute.
Add ½ cup of the simmering broth and stir until almost completely absorbed, about 2 minutes. Continue cooking the rice, adding the broth ½ cup at a time, stirring constantly and allowing each addition of broth to absorb before adding the next, until the rice is tender and the mixture is creamy, about 25 to 30 minutes total. Remove from the heat and stir in the Parmesan cheese.
Transfer the risotto to a serving bowl and sprinkle with the parsley. Serve immediately with additional Parmesan cheese to pass at the table.