Melt the butter in a large frypan over medium heat. Add the onion and garlic then fresh mushrooms. Cook until the onions are translucent.
Stir in curry powder until well blended. Place the meat strips in the frypan and fry until evenly browned.
Dissolve the stock cubes in the boiling water then stir into the frypan. Add the mushroom stems and pieces and dried shiitake mushrooms. Let the mixture simmer over medium heat until most of the liquid has evaporated; about 20 minutes.
Meanwhile, bring a large saucepan of lightly salted water to a boil. Add the pasta and cook until tender; about 7 minutes. Drain.
Reduce the heat under the frypan to low and pour in the cream stirring until the sauce is an even colour. Simmer for about 5 minutes but do not boil. Serve over pasta.