Remove the turkey meat from the sausage casings and dispose of the casings. Season the turkey with salt and freshly ground black pepper. Wash and coarsely chop the mushrooms and grate the cheese. Place 2 tablespoons of olive oil in a large pan over high heat, add the turkey and sauté it (breaking any large pieces) until golden brown. Remove the meat from the pan and set aside.
Pour a further 2 tablespoons of olive oil into the pan and add the chopped mushrooms. Season with salt and freshly ground black pepper and sauté for about 5 minutes until all the liquid from the mushrooms has evaporated. Add the peas and sauté for a further 4 minutes. Return the turkey meat to the pan and cook for another 3 minutes, then remove the pan from the heat and set aside.
Bring 10 pints (about 6 litres) of salted water to the boil in a large pot. Add the pasta and cook for about 6-8 minutes until al dente. Drain in a colander then return the pasta to the pot and add the meat mixture. Combine the ingredients thoroughly and gently cook over medium heat for 5 minutes. Drizzle in the remaining olive oil and, if the mixture is dry, do not hesitate to add more olive oil. Check the seasoning, remove from the heat and add the grated cheese. Stir well and serve in large bowl.