In a large skillet, cook bacon over moderate heat. Once crisp, remove and crumble into bits. Remove all the bacon fat off the skillet, leaving only about 2 tablespoons. Saute the sliced mushrooms and garlic for 3 minutes or until tender.
Mix in the drained cooked pasta, Parmesan cheese, whipping cream and pepper. Let it simmer, bring heat to medium-low. Stir often and cook until sauce is thick. Mix in the bacon along with green onions and serve.