Sometimes the original truly is best. This is the classic recipe without getting fancy with modifications. The key to making this a show stopper is to make every one of the few ingredients the best quality you can find. Oh, and if anyone ever tries to sell you on a "traditional" pasta with pesto that doesn't include potatoes and green beans, you can, with confidence, tell them they are wrong. —sumradagnoth
Pesto alla Genovese
packed young (small) basil, leaves oly
clove garlic, whole
best quality extra-virgin olive oil, from Liguria
This would all traditionally be done with a stone mortar and pestle, but for the sake of convenience, we will use a food processor. Be sure to select very young, tender basil for the pesto, and remove the stems.
Add the basil, garlic, pine nuts (which you can toast if you prefer a more pronounced flavor) and salt to the food processor and begin processing. Slowly add the oil in a thin stream until a thick paste forms. Be sure not to over-process the mixture.
Transfer the mixture to a bowl and fold in the cheese.
You can place this in a jar, covered with a bit of oil, and refrigerate until ready to use. Do not heat the pesto before using it or adding it to whatever recipe you desire.
Bring a large pot of copiously salted water to boil. Let the pesto come to room temperature, if you had it in the refrigerator.
Add potatoes to boiling water and cook until just tender. Remove potatoes and cut them in half or quarters, depending on their size.
Add pasta to the water and cook until just al dente. Add the haricot verts to the same pasta water about 2 minutes before the pasta would be done.
In a large serving bowl, add the pesto and a small ladle of the pasta cooking water. The pesto should be mixed with enough water to loosen it a good bit.
Drain the pasta and haricot verts, add to the bowl with the pesto and the reserved potatoes. Toss well and serve with grated parmigiano-reggiano.