Bring a large pot of lightly salted water to a rolling boil and cook the spaghetti according to package directions until al dente.
While the pasta cooks, finely chop the red chili (de-seeded), peel and finely chop the garlic clove removing the internal germ, and finely chop the parsley.
In a large bowl combine the extra virgin olive oil, chopped garlic and chopped chili; season with salt and freshly ground black pepper and whisk with a fork to blend.
When the pasta is done, reserve about 1 cup of the cooking water, then drain the spaghetti.
Transfer the hot spaghetti to the bowl with the oil, garlic and chili; add the grated pecorino and about two tablespoons of the reserved cooking water, then quickly toss and mix to form a creamy sauce, adding more cooking water as needed to reach a silky consistency.
Stir in the chopped parsley and, if using, the toasted pine nuts, toasted slivered almonds and toasted breadcrumbs; taste and adjust seasoning, then serve immediately.