Melt butter in a frying pan and fry breadcrumbs until golden-brown and crisp.
Mix in half the parsley, the thyme, salt, and pepper.
Boil spaghetti in salted water until cooked, then drain and toss with three tablespoons of olive oil.
Steam razor clams with 100ml of white wine in a covered pan for 3 minutes until opened.
Strain the clams, reserving the liquid, then remove meat from shells, clean, and chop.
Fry chorizo in the remaining oil for 3 minutes, then add clams, remaining wine, garlic, and chillies.
Cover and cook for 4 minutes until clams open, then add razor clams, reserved liquid, spaghetti, and remaining parsley.
Season the mixture with salt and pepper to taste.
Serve the spaghetti in bowls topped with the cooking juices and toasted breadcrumbs.