Check the clams and discard those with broken shells.
Thoroughly rinse the clams under running cold water. Use a brush (can be a simple toothbrush) to scrub off the dirt from the crevices and the outside.
In a large bowl, dissolve 30g of sea salt per each litre of cold water. Place the clams into the bowl and make sure they are fully submerged.
Allow the clams to sit in the water for 1.5-2 hours, then take them out with a blotted spoon.
Rinse once again under running water.
Heat a medium pot to medium-high. Pour in the clams, cover and cook for 3-5 minutes until they open. Discard those that haven't.
Reserve the liquid they have produced. If the liquid still seems not clear enough, strain it through a fine sieve.
Allow the clams to cool and remove the meat from about 2/3.
In a large pan, heat 2 tbsp of extra virgin olive oil to medium.
Add garlic and chili flakes (if using) and fry for a couple of minutes until the garlic turns fragrant.
Add the clams with their liquid, half of the parsley, 2 more table spoons of evoo and 2/3 glass of white wine.
Simmer until the alcohol evaporates and turn the heat off.
Cook spaghetti one minute short of al dente.
Drain and reserve 1/2 cups of starchy pasta cooking water.
Add the spaghetti to the pan with clams and heat through. Add a little pasta cooking water if the pasta seems dry.
Taste and adjust for salt, if necessary.
Sprinkle with the remaining parsley, finish off with a grind of black pepper mill and serve immediately.