Bring a large pot of lightly salted water to a boil. Add pasta and olive oil. Cook for 7 minutes, or until tender. Drain.
Meanwhile, melt butter in a skillet over low heat. Add the mushrooms, and cook until soft and dark. Stir in the garlic, Italian seasoning, salt, white wine, and chicken broth. Increase the heat to medium, and cook stirring constantly for about 5 minutes.
Reduce heat to low, and stir in the sour cream until smooth. Stir in cornstarch, and simmer for a minute to thicken. Stir in pasta, or spoon sauce over pasta. Serve, and top with grated Parmesan cheese.