Bring a large pot of salted water to a boil for the spaghettini.
Peel and thinly slice the garlic.
Crumble the pepperoncini into pieces.
Heat the olive oil in a pan, then sauté the garlic and the pepperoncini.
Sauté briefly, because the garlic can be bitter if burned.
Remove the pan from the heat.
Cook the spaghettini in the boiling salted water according to the package directions until al dente.
Rinse the parsley and pat dry. Remove the leaves from the stems and finely chop.
Shortly before the spaghettini is done cooking, heat the pan with the garlic. Mix 3-4 tablespoons of the pasta cooking water into the garlic mixture.
Drain the spaghettini in a colander, then add to the pan. Season to taste with salt and pepper.
Sprinkle the parsley over the pan, and mix until thoroughly combined.
Arrange the spaghettini on warmed plates, garnish with shaved parmesan cheese, and serve immediately.