Bring a large pot of lightly salted water to a boil and cook the spaghetti according to package directions until al dente, reserving 1 cup of the cooking water before draining.
While the pasta cooks, finely chop the de-seeded red chili, mince the garlic after removing the inner germ, and finely chop the parsley.
In a large bowl, combine the extra virgin olive oil, minced garlic and chopped chili; season with salt and pepper and whisk with a fork for a few seconds to emulsify.
Add the hot drained spaghetti to the bowl with the oil mixture and toss to coat.
Add the grated pecorino and about two spoonfuls of the reserved pasta water, then mix vigorously to form a creamy sauce, adding more pasta water as needed to reach the desired creaminess.
Stir in the chopped parsley, toasted pine nuts, toasted slivered almonds, and toasted breadcrumbs (if using) until evenly distributed.
Adjust seasoning with salt and pepper if needed and serve immediately.
