In a mortar and pestle, mix garlic and basil, then add pistachios. Add in olive oil slowly. Start with half a cup, then add more if necessary. Finally add parmesan.
In a deep, flat bottomed saucepan, boil water with salt added. Estimate the amount water to just be enough to cover the pasta. Add pasta and cook according to the time stated in the package.
When water has ALMOST but not completely dry up, stir in the pesto paste and mix thoroughly. You need the water to make a sauce.
Add in lemon juice. If sauce is too dry, add more olive oil.
Check for seasoning. Add cracked black pepper and salt (if necessary). Your pasta is ready to be served!