Bring a large pot of water to a rolling boil and add 1 tablespoon of sea salt and the pasta to the pot. Cook for 7 to 8 minutes, or until al dente.

While the pasta is cooking, make the sauce. Add the olive oil to a large frying pan and heat over medium-high heat. Once hot, add the onion, the remaining ¼ teaspoon sea salt, and the black pepper. Cook for 3 to 4 minutes, or until the onion is soft and light golden brown.

Add the garlic and cook for 30 seconds, then add the Calabrian chili pepper paste and cook for another 30 seconds. Add the passata sauce, sugar, and basil stem, and stir to combine. Bring to a simmer, then reduce the heat to medium to bubble gently.

Once the pasta is almost done cooking, add the whipping cream to the sauce and stir to combine. Then drain the pasta and add it to the pan with the sauce. Toss to combine and add ½ cup of pasta water and the Parmigiano Reggiano cheese. Cook over medium heat for 2 minutes, to allow the sauce to absorb into the pasta.

Transfer the pasta to plates and garnish with extra grated Parmigiano Reggiano cheese and chopped basil leaves. Serve immediately and enjoy!