Preheat the oven to broil.

Set a large, 4 to 6-quart stockpot filled with water over high heat and bring to a boil. Season the water with the kosher salt, 2 tablespoons olive oil and add the spaghetti. While the pasta cooks, set a 14-inch saute pan over medium-high heat and add the olive oil. Once the oil is hot, add the onions and garlic and cook, stirring occasionally, until soft and slightly caramelized, 3 to 4 minutes. Add the oregano and basil. Add the diced tomatoes, tomato sauce and tomato paste and stir well to combine. Continue to cook the sauce until it is slightly reduced, about 4 to 5 minutes. Add the heavy cream to the pan. By this time the pasta should be almost al dente. Drain pasta, reserving 1 cup of pasta water. Add the pasta and the 1 cup of reserved cooking water to the sauce in the pan and and season with the salt and pepper. Continue to cook, tossing the pasta, until it is well coated with the sauce and most of the liquid has evaporated, about 2 to 3 minutes. Serve with the Parmesan and top with chopped basil.