For the pesto:
1 cup fresh flat-leaf parsley leaves
2 Tbsp roughly chopped walnuts
1 large clove of garlic
1 tsp black pepper
1/4 tsp kosher salt
4 Tbsp extra virgin olive oil, divided
2 Tbsp grated Parmigiano-Reggiano cheese
For the pasta:
1/2 lb short pasta (farfalle, penne, rotini, etc.)
1 small onion, diced
1 cup fresh peas
1/4 cup dry white wine
1/4 cup grated Parmigiano-Reggiano cheese
Fresh black pepper, to taste
Extra walnuts, for garnish (optional)
Bring 4 quarts of water to boil in a large pot on the stove. Cook the pasta until al dente (1 minute less than the package directions); drain (do not rinse) and set aside.
While the water is coming to a boil, combine the parsley, walnuts, garlic, 1 teaspoon of black pepper, salt, olive oil, and 2-3 tablespoons of Parmigiano-Reggiano cheese in a small food processor, and process to a smooth paste.
In a nonstick frying pan, heat the remaining olive oil, and sauté the onion for 2 minutes over medium-low heat, until translucent. Add the peas, and cook for 2 minutes. Then, add the pasta and the parsley-walnut pesto from the food processor. Stir to make sure the pesto is distributed throughout all the pasta.
Pour in the wine, and add the 1/4 cup of cheese. Stir to mix everything together, and add black pepper to taste. Cook over medium-low heat for 2 minutes, stirring frequently, until everything is heated through and the cheese has melted.