Pesto alla Genovese

[Clove]

I just made my firstPesto Genovese of the season.
There are many varriations of un-cooked chopped topping for pasta used all thoughout Italy.
This one from Genoa, in Liguria (just north of Tuscany), is the most widly used in the US.

Ingredients:

2 C packed fresh basil leaves
1/4 C of pine nuts
pinch of salt
1 clove of garlic
1/4 to 1/2 C of Extra Virgin Olive Oil
1/2 C freshly grated Parmigiano Reggiano cheese

Method:

Take first 4 ingredients and put them in the work bowl of your food processor.
Pulse until finely chopped. (Or use a mortar and pestle like the Italians do)
Drizzle the olive oil in with motor running until the mixture becomes a thick paste (pesto).
Add the cheese and combine quickly.
Serve immediately or store, refrigerated, covered with a thin layer of olive oil in an air tight container

Traditionally it is tossed with trenette (a thinner version of linguine), green beans, and bits of potato, or with a short hand rolled pasta called trofie.

Notes:
The basil will turn very dark if left exposed to the air. It will still taste fine but it will lose the "garden green" color.
I have blanched and shocked my basil before chopping to lock-in the green color but only at the end of the basil season when I harvest a ton of leaves. Otherwise I just pick what I need for the recipe I'm doing and it stays green thorough service.
Some chefs add ground up vitamin C to their pesto for the same reason.
I have no experience with this chemical preservation method.