Melt butter in a heavy, large skillet over a medium low heat. Add garlic and mushrooms and a generous amount of fresh grated coarse black pepper. Cook until mushrooms exude their juices, stirring occasionally, about 5 minutes. Add shrimp and cook until they are starting to turn pink. Add cream and shrimp until sauce thickens slightly, about 3 minutes and season with salt. Meanwhile, cook pasta in large pot of boiling, salted water. Add oil to water to keep pasta from sticking together. Drain well. Add pasta and cheese to sauce and stir until cheese melts. Transfer to plates. Sprinkle with parsley and serve.