Bring a large pot of lightly salted water to a boil. Cook pasta in boiling water for 6 to 8 minutes or until al dente; drain.
Meanwhile, heat oil over medium-high heat in a large frying pan. Cook and stir mushrooms in oil until tender. Remove mushrooms from pan, and set aside.
Combine prawns, champagne and salt in the frying pan, cook over high heat. When liquid just begins to boil, remove prawns from pan and set aside. Add shallots and tomatoes to champagne; boil until liquid is reduced to 1/2 cup, about 8 minutes. Stir in 3/4 cup cream; boil until slightly thick, about 1 to 2 minutes. Add prawns and mushrooms to sauce, and heat through. Adjust seasonings to taste.
Toss hot, cooked pasta with remaining 1/4 cup cream and parsley. To serve, spoon prawns with sauce over pasta, and top with Parmesan cheese.
Delicious! I wasn't sure about the prawn/mushroom combo but I had both ingredients to use up so tried it; the tomatoes make it work! I used prosecco and added a tsp of tomato paste. Perfect! - 28 Feb 2015