Soak the shrimp in a bowl of cold water with the lemon cut in half and a little of the coarse salt for 30 minutes.

Place a medium-sized pot of cold water over medium heat and bring to a boil. Add coarse salt to taste.

Drain the shrimp, rinse them under cold running water, and add to the pot of boiling water. Cook for 2 minutes. Drain the shrimp, then shell and devein them. Place shrimp in a crockery or glass bowl.

Coarsely chop the onion and finely chop the garlic and soak in a bowl of cold water for 30 minutes.

Clean the tomatoes, then cut them, without removing seeds and skin, into 1/2-inch cubes and place them on top of the shrimp along with the parsley. Cut the celery into pieces about 1 X 1/2 inch and add it to bowl. Drain the onion and garlic and add to bowl. Pour the oil over and season with salt and pepper.

Do not mix, but cover the bowl and refrigerate for at least 1 hour before using

When ready to serve, Bring a large pot of cold water to a boil. Add coarse salt, then the pasta, and cook according to package instructions.

Drain the pasta and transfer to a large serving platter. Mix the sauce well and pour over pasta. Mix pasta and sauce. Arrange the basil leaves all over, and serve with more freshly ground black pepper.