In a large dutch oven, boil pasta until al dente, drain and reserve ½ cup of the pasta water.
While the pasta cooks, place the chicken in a medium bowl and season with salt, pepper, and Italian seasoning.
Return the pot to the stove over medium-high heat and add olive oil and butter once heated. Saute the chicken until browned and mostly cooked through, about 3-4 minutes. Remove to a plate.
In the pot, saute garlic and tomato paste and cook for 30 seconds. Reduce the heat to low and add the tomato sauce, ¼ cup pasta water and chicken and bring to a simmer for 6-8 minutes.
Stir in the cream and add the cooked pasta and return to a simmer, tossing to combine and heat through. Add in some of the reserved pasta water if the sauce is too thick.
Serve hot with parmesan cheese and freshly chopped basil, if desired.
Notes
San Marzano tomatoes are the best choice for this sauce, as they have a naturally balanced flavor with more sweetness and less acidity. If you can't find them in the form of tomato sauce you can use crushed or whole tomatoes, and crush them yourself in a large bowl with a fork or potato masher or puree them with a stick blender.If you can't find the san marzano variety you can add in a teaspoon or two of sugar or a ¼ teaspoon of baking soda to help bring balance and neutralize the acidity of the tomatoes.