Bring a large pot of salted water to a boil and cook the fettuccine according to package directions; drain and keep warm.
While the pasta cooks, heat 2 tablespoons of the oil from the sun-dried tomato jar in a large skillet over medium heat.
Add the chopped sun-dried tomatoes, minced garlic, and red pepper flakes to the skillet and sauté for about 1 minute until fragrant.
Sprinkle in the flour and cook, stirring constantly, for 2 minutes to form a roux.
Reduce heat to low and pour in the chicken broth, stirring to combine.
Whisk the cornstarch into the milk until smooth, then add it to the skillet along with tomato paste, dried basil, dried parsley, onion powder, dried oregano, salt, and pepper.
Bring the sauce to a gentle simmer and cook, stirring, until it thickens slightly, about 5 minutes.
Lower the heat to low and stir in the cubed reduced-fat cream cheese until melted, then add the freshly grated Parmesan and stir until smooth.
Add the shredded mozzarella and stir until melted, then toss in the cooked fettuccine until the pasta is evenly coated with the sauce.
Taste and adjust seasoning with additional salt, pepper, or red pepper flakes as desired, then serve topped with extra grated Parmesan and fresh basil if using.
