Cook the pasta in a pan of boiling salted water according to the packet instructions, then drain, reserving a mugful of starchy cooking water. Meanwhile, for the pangrattato, put 2 tablespoons of olive oil into a large frying pan on a medium-high heat with the breadcrumbs and chilli flakes. Peel and finely grate in the horseradish, then fry for 5 minutes, or until crisp, stirring regularly. Tip into a bowl and put aside. Return the frying pan to a medium heat with 2 tablespoons of olive oil. Peel, finely slice and add the garlic, strip in the thyme leaves, then tear in the dried peppers, discarding the seeds. Fry for just 1 minute, then toss in the drained pasta, loosening with a little reserved cooking water, if needed. Season to perfection, divide between warm bowls, drizzle lightly with extra virgin olive oil and generously sprinkle over the pangrattato.