Clean and wash the leek and cut into fine rings. Remove the scampi from their skin, except for the tails. Cut lengthwise on the curved side and remove the black intestine.
Wash the scampi and pat them dry. Peel garlic and press it through a garlic press. Cook spaghetti in plenty of boiling salted water for 8-10 minutes until al dente. In the meantime heat oil in a pan.
Fry the leek for 1-2 minutes. Season with salt and pepper. Remove and keep warm. Steam garlic in frying oil until golden brown. Add the scampi and fry for about 4 minutes, turning. Season with salt and pepper.
Take it out. Deglaze frying oil with lemon juice and cream. Season with salt and pepper and simmer for about 2 minutes at high heat. Wash parsley, dab dry, pluck leaves from the stalks and chop coarsely.
Drain the spaghetti and serve with scampi and leek. Pour sauce over it and sprinkle with parsley.