In a medium saucepan, bring the chicken stock to a simmer. Keep warm.
In a large saucepan, heat the olive oil. Add the onion, season with salt and pepper and cook over moderate heat, stirring, until softened, about 5 minutes. Add the rice and cook, stirring, for 1 minute. Add the wine and cook, stirring until the wine is absorbed. Add 1 cup of the warm stock and cook over moderate heat, stirring constantly, until nearly absorbed. Continue adding the stock 1/2 cup at a time, stirring constantly, until it is nearly absorbed between additions. The risotto is done when the rice is al dente and suspended in a thick, creamy sauce, about 20 minutes total. Season with salt and pepper.
Meanwhile, in a large skillet, melt the butter. Add the mushrooms and shallot, season with salt and pepper and cook over moderately high heat, stirring occasionally, until softened and browned, about 10 minutes. Scrape the mushrooms into the risotto and stir in the cheese and parsley. Serve immediately.