Bring a large pot of heavily salted water to a boil. Cook rigatoni until just under al dente — about 1 minute less than the package directions indicate.

Before draining, scoop out at least 1/2 cup of pasta water and set it aside. Drain the pasta and set it aside. Do not rinse.

Heat olive oil and butter in a large skillet over medium heat. Once the butter melts, add the minced garlic and red pepper flakes. Cook for 90 seconds, stirring constantly, until fragrant but not browned.

Add the chopped sun-dried tomatoes and stir to combine. Cook for 2 minutes, allowing them to deepen in flavor.

Pour in the white wine or chicken broth and let it reduce by half, about 2 to 3 minutes.

Reduce heat to medium-low. Add 1/4 cup of reserved pasta water to the skillet and stir to combine.

Slowly pour in the heavy cream while stirring. Let the sauce come to a gentle simmer and cook for 3 to 4 minutes until slightly thickened.

Stir in the freshly grated Parmesan a handful at a time, letting each addition fully melt before adding the next. Add Italian seasoning and season with salt and pepper to taste.

Add the cooked rigatoni to the skillet and toss to coat over medium-low heat for about 2 minutes. If the sauce is too thick, add a splash more pasta water. If using spinach, fold it in now and let it wilt for 30 seconds.

Serve immediately, garnished with fresh basil and extra Parmesan if desired. The sauce should coat the pasta and slide slowly off a spoon — that's your cue it's ready.