1) If using fresh peas, shell them from the pods and blanche them in boiling water for 2-3 minutes. Place the peas in cold water when done, then drain.
2) On a medium-low heat, begin cooking the pancetta in a saucepan, until the fat renders.
3) Add the onions, cooking until translucent and pancetta gets crisp.
4) Add cooked or frozen peas and chicken stock.
5) Cover after it comes to a boil, then turn to medium-low for 10 minutes, or until peas have cooked.
6) Cook pasta in a large pot of boiling, salted water. Test after 3 minutes. Drain.
7) Toss hot pasta, add pancetta, onions, and peas. Mix.
8) Transfer the hot pasta to a serving dish. Garnish it with oregano and grated Parmesan cheese. Season with salt and pepper and serve.