Boil a large pot of water to cook the spaghetti (Reserve a quarter of a cup of the cooking water).
Finely chop parsley leaves.
Peel and finely chop garlic.
Zest the lemon and juice.
In a frying pan, warm olive oil to medium-hot, but not smoking. Add breadcrumbs, chilli flakes and a sprinkle of sea salt and sauté for about 5 minutes, or until breadcrumbs are golden.
Add garlic and cook for another minute, toss in parsley and remove from the heat, then stir through lemon zest.
Season with pepper and a little more sea salt to taste, then remove from pan and place in a bowl.
Return frying pan to the stove and add the cooked spaghetti, a little more oil and the reserved cooking water. Toss well and cook for a further 30 seconds. Stir through lemon juice, mix well.
Serve sprinkled with breadcrumb mixture and a liberal amount of parmesan.