Cook the spaghetti in salted water according to the instructions on the packet until al dente. In the meantime, roughly grate the white bread or crumble it with your hands. Peel garlic and chop finely.
Heat the olive oil in a large pan. Fry the garlic and chilli flakes briefly in it, then add the white breadcrumbs and roast until golden brown.
Lift the cooked spaghetti out of the cooking water with pasta tongs and toss well in the pan with the breadcrumbs, the chopped parsley and 3 tablespoons of pecorino cheese. Season to taste with salt and pepper. Serve the rest of the pecorino separately.