Gently wash the basil in cold water and pat dry with a towel. Crush a clove of garlic in a mortar and add some basil (30 leaves per clove), and then a pinch of salt. Using a gentle circular motion, use the mortar to pound the basil until it turns into a bright green oily liquid. Repeat this process until all the basil and garlic are added. Add the pine nuts and gently crush them into the mixture. Add the cheese and slowly drizzle in the olive oil while mixing together. Avoid turning the sauce into a puree; it should have a fine, leafy consistency.
Bring a large pot of salted water to a boil.
Cook the pasta until al dente (about 2 minutes less than package directions). Drain, retain some of the cooking water, and place in a large, warm serving bowl. Slowly mix in the pesto sauce. Add some of the cooking water if the pasta seems too dry.
Serve immediately with grated Parmigiano.
* If you don’t have a mortar and pestle, you can use a food processor, but use it on pulse mode, so as to avoid turning this into a puree. There should be a fine, leafy consistency.