Slice the squid into cubes and the calamari into thick slices. Cut any tentacles in half.
1 squid
Use scissors to cut the legs off of the scampi and the optional mantis shrimp.
4 scampi, 4 mantis shrimp
Steam the Shellfish
Cover the bottom of a large saucepan or skillet with olive oil. Over medium-high heat, sauté 2 cloves of garlic in the oil to infuse the oil with garlic.
½ cup olive oil, 5 cloves garlic
Add the mussels and clams to the pan. Cover and steam the shellfish over medium-high heat until most of the shells have opened up. Discard any un-opened shellfish as they may be unsafe to eat.
1 lb mussels, 1 lb clams
Strain the broth produced by the shellfish. Set aside for use in the sauce.
Remove the shellfish meat from half of the clams and mussels. Let the meat rest in the strained broth until ready to use in the sauce.Set aside the shellfish still in their shells. We'll use this to decorate the dish. Discard the garlic cloves.
Cook the Scampi, Squid and Calamari
Cover the bottom of a large saucepan or skillet with olive oil. Over medium-high heat, sauté 2 cloves of garlic and the red pepper (halved) in the oil to infuse the oil.
1 fresh red chili pepper
Add the scampi to the pan. Cook uncovered in the oil for about 3 minutes, flipping the scampi halfway through. Then, remove the cooked scampi and set aside. Discard the garlic and pepper.
Add the calamari and squid to the pan with the flavored oil. Cook uncovered for about 3 minutes over medium heat. Season with a small pinch of salt and black pepper.
2 calamari, black pepper
Add the white wine to deglaze the pan. When the wine has mostly evaporated, time to make the sauce!
½ cup white wine
Make the Seafood Spaghetti Sauce
To the pan with the calamari and squid, add the tomato purée and the halved cherry tomatoes. Season with a pinch of salt.
10 cherry tomatoes, 2 tbsp tomato purée, fine salt
Cook uncovered over medium-high heat for about 3 minutes.
Add mantis shrimp (optional), shrimp, and the seafood broth with the cooked shellfish meat.
½ lb shrimp
Cover and cook the sauce for 5 minutes.
Finish with Spaghetti
Cook the spaghetti to 'al dente' according to package directions.
¾ lb spaghetti
Strain and add the spaghetti to the pasta sauce. Add the minced parsley. Toss to combine the spaghetti with the seafood sauce.
1 handful flatleaf parsley
Add the scampi and mussels and clams in the shell back to the pan for serving.