Put half of the olive oil in a large pan or saucepan. Sauté the whole shrimps over medium-high heat until they turn brown. Transfer them to a plate.
Season the peeled shrimps with salt and pepper and sauté them in the pan in two portions. Once they get colored on both sides, take them out on a plate.
Put the rest of the olive oil in the pan and sauté the onions, garlic and chili flakes. When the onion softens and gets a little colored, add the tomato paste. Stir to bring to a boil and add the white wine. Let the alcohol evaporate for 1 minute. Add the chopped tomatoes, the Classic diced tomatoes and half of the parsley. Season with salt and pepper.
Put all the shrimps back in the pan. Simmer for 5-6 minutes until the sauce sets.
Meanwhile, boil the tagliatelle in plenty of salted water for 2 minutes less than the time indicated on the package. Drain and place in the pan along with the sauce and the shrimps. Stir well to bring everything to a boil for 2 minutes.
Transfer the pasta to a serving platter. Sprinkle with extra parsley if desired and serve immediately. Enjoy!