Spinach and Mushroom Fettuccine Alfredo is a vegetarian twist on the classic recipe. Along with the basic ingredients, this version includes sautéed spinach and mushrooms. Start by sautéing sliced mushrooms in butter until they release their moisture and turn golden brown. Add fresh spinach leaves and cook until wilted. Prepare the Alfredo sauce as mentioned in the classic recipe. Once the sauce is ready, add the sautéed spinach and mushrooms to the sauce and toss in the cooked fettuccine pasta. Serve hot and garnish with grated Parmesan cheese. This variation adds a delightful earthy flavor to the traditional Fettuccine Alfredo.