Bring a large pot of lightly salted water to a boil. Cook pasta for 8 to 10 minutes, or until al dente; drain.
Melt butter with olive oil in a large frypan over medium heat. Saute garlic and mushrooms until tender. Stir in yabbies and spring onions; reduce heat to low and cook 5 minutes. Stir in cream, Parmesan cheese and parsley. Simmer for 5 minutes. Season with salt and pepper and serve over hot linguine.