Bring a large pot of lightly salted water to a boil. Add pasta and cook for 6 to 8 minutes or until al dente; drain.
Heat olive oil over medium-high heat in a large frying pan. Cook and stir mushrooms until tender. Remove mushrooms from the pan and set aside.
Combine shrimp, champagne, and 1/4 teaspoon salt in the frying pan and cook over high heat. When liquid just begins to boil, remove shrimp from the pan. Add shallots and tomatoes and boil until the liquid is reduced to 1/2 cup, about 8 minutes. Stir in 3/4 cup cream and boil until slightly thick, about 1 to 2 minutes. Add shrimp and mushrooms back to the sauce and heat through. Adjust seasonings to taste.
Toss hot cooked pasta with remaining 1/4 cup cream and parsley.
To serve, spoon shrimp and sauce over the pasta and top with parmesan cheese.