For the Pesto:

• Add the pine nuts to a small skillet over medium heat and toast until golden brown, approximately 2-3 minutes.
• In the bowl of a food processor, add 1/2 the pine nuts, 3 cups basil, 2 garlic cloves, 1/2 cup cheese and lemon zest. Process the ingredients until finely chopped, approximately 30 seconds.
• While the processor is still running on low speed, slowly drizzle 3/4 cup of olive oil and prices until a smooth paste begins to form. Stop the food processor and scrape down the sides of the bowl.
• Add the remaining pine nuts, basil, garlic and cheese to the bowl. Pulse until finely chopped.
• Using a rubber spatula, transfer the pesto sauce to a bowl and stir in the remaining olive oil. Season with salt and pepper, to taste.
• This step can be done up to 5 days in advance. Store in an airtight container in the refrigerate until ready to use.
• Bring a large pot water to a boil and season with salt.
• Add the pasta to the water and cook according to the package instructions to al dente.
• Transfer the pasta to a large bowl and reserve 1 cup of the cooking liquid.
• Add the pesto to the pasta and toss to coat.
• Stir in the remaining cooking liquid 1/4 cup at a time until the desired consistency. (You may not need all the cooking liquid.)
• Season with salt and pepper, to taste.
• Serve hot with parmesan cheese, if desired.