Cook spaghetti until al dente, over medium high heat
Meanwhile, prepare pesto sauce.
Add all ingredients except olive oil in a food processor. Pulse several times until its almost creamy. Slowly add olive oil while food processor is running, this step helps to keep the oil from separating. Make sure to scrape down food processor with rubber spatula and pulse several more time. Set aside.
When the spaghetti is cooked, drain water and pour in ½ cup of pesto sauce and toss until pasta is coated.
Add salt and pepper of desired. Serve with parmesan cheese and basil leave