Trenette al pesto alla genovese (trenette pasta with genoese basil sauce)

fresh basil 2 bunches (approximately 100 grams)
pine nuts 2 tablespoons
grated parmesan cheese 4 tablespoon
grated aged pecorino cheese 4 tablespoons
extravirgin olive oil 8 table spoons
pinch of salt
2 cloves of garlic
1 potato
fresh green beans 100 gr 4 oz
Trenette pasta or linguine pasta 400 gr. 8 oz

1. Wash the basil, remove stalks and pat dry with a towel, place the peeled garlic in the blender with the pine nuts and a pinch of salt, blend until the garlic cloves are mashed, add the basil and a little oil, blend until the basil is chopped completely, add the cheese, blend briefly to mix, ad the oil alittle at the time as the blender is turning until you obtain a creamy green sauce. Remove from the blender put in a jar or plastic container, cover with a 1cm. Olive oil and place in the refrigerator to cool.
2. Cut the green beans cut into 5 cm pieces, start to cook the green beans 3 minutes before the pasta, add the pastaand cook "al dente" in plenty of salted water, together with the beans and diced potato.
3. Strain, keeping some of the water aside, put back in the pot, add a tablespoon of sauce per person and one for the pot, add a little of water you kept aside to dilute the pasta, mix briefly and serve.