Bring a large pot of well salted water to boil Add pasta and cook according to package directions.
Add peas during the last 3-4 minutes.
While pasta is cooking, render pancetta until slightly crispy. Drain on paper towel.
Reserve about 1/2 cup pasta water. Then drain pasta & peas and return it to hot, dry pot.
Add red pepper flakes, salt, olive oil, cheese, pancetta and gently stir until well combined. If not saucy enough add a little pasta water ... even a pat of butter.
Spoon into bowls and garnish with more cheese and parsley, if you have it.