Begin by heating your oil in a large frying pan over a medium heat, add in the onion and allow to soften and turn sticky and translucent. This should take around 6-8 minutes and be careful to not allow the onion to turn brown. You can reduce the heat if it begins to. Next add in the garlic and anchovy fillets then using the back of your spatula begin to break up the fillets and combine with the onion. Reduce the heat and allow the onion to continue to cook while you get your pasta on. Next prepare your courgette ready to add once the pasta has cooked. You can also grate your Parmesan and chop your parsley too.
Bring a large pan of water to the boil, add in a good sprinkle of salt and once the water is boiling add in the spaghetti and stir for the first minute or so. Bring the water back to the boil then leave the lid off and allow to cook for 10-12 minutes or until the pasta is al dente (still has a slight bite to it).
Just before you add in your cooked pasta add in the courgette spirals and increase the heat. Allow to cook for a minute then drain the pasta and add this also thoroughly combining all ingredients. Add in half of the grated Parmesan, parsley and pepper and check the seasoning adding any additional salt if necessary.
Serve with an extra helping of Parmesan.