1. In a large saucepan, boil water and cook pasta as directed.
2. In a blender or food processor, take chopped basil, garlic, cheese, walnuts and olive oil; process until a smooth paste is formed.
3. When the pasta is cooked, drain well and transfer to a large serving bowl.
4. Add the basil pesto and mix well.
5. Season with salt and pepper to taste.
6. Sprinkle with grated Parmesan cheese if desired.