Bring a large pot of salted water to a boil. Cook the spaghetti according to the package directions until Al Dente. Drain and reserve 1 cup of the salty pasta water.
Meanwhile heat up your largest skillet on medium low flame.
Add a lug of olive oil, the garlic and red pepper flakes. Stir quickly making sure not to burn the garlic. Add in the clams and mussels and toss them around.
Pour in the white wine and cover with a lid. Cook for about a minute or so until the clams start to open.
Add the shrimp to the skillet with clams and give it a stir. Cover and cook for another minute or so.
Once all the clams and mussels have opened and the shrimp is almost cooked, add the squid tentacles. Cook another 30 seconds or so until they curl up.
Taste for seasonings and add more sea salt if needed. ( Remember that shellfish will spit out a lot of sea water during cooking, so wait till the end to season)
Meanwhile warm up the sauce in a saucepan. Pour the sauce over the seafood and toss to coat well.
Add the cooked spaghetti pasta to the skillet with the seafood and toss to coat in the sauce. Add a little bit of the reserved pasta water if needed to stretch out the sauce.
Transfer your seafood spaghetti to a serving platter, drizzle with a lug of olive oil and sprinkle with the basil and parsley.