-Cook the spaghetti in salted boiling water until al dente. Before draining, scoop out one ladle of pasta water and set it aside. Drain the pasta and keep it ready.

-Heat olive oil in a large skillet over medium heat. Add the chopped onion and sauté until softened and slightly translucent, which usually takes about three to four minutes.

-Add the chopped garlic and cook briefly until fragrant. Stir constantly to prevent burning while allowing the aroma to develop.

-Add butter, tomato paste, flour, Italian seasoning, salt, and pepper. Stir thoroughly and allow the mixture to cook for about two minutes. This step deepens the tomato flavor and removes the raw taste from the flour.

-Slowly pour in the chicken broth while stirring continuously to prevent lumps from forming. Add the heavy cream and let the mixture simmer gently until the sauce begins to thicken.

-Stir in the chopped sun-dried tomatoes and one tablespoon of oil from the jar. The oil enhances the sauce and adds a deeper tomato flavor.

-Add shredded basil and Parmesan cheese. Stir until the cheese melts completely and blends into the sauce.

-Pour in the reserved pasta water to loosen the sauce and help it coat the pasta evenly. Taste and adjust seasoning by adding garlic powder, additional salt, pepper, or Italian seasoning if desired.

-Add the cooked spaghetti directly into the skillet. Toss thoroughly until every strand is coated with the creamy sauce.

-Serve immediately while hot. Garnish with additional basil or Parmesan cheese if desired.