Bring a large pot of water to a rolling boil and add 2 tablespoons kosher salt.
Add 8 ounces cavatappi pasta and cook until 1 minute less than the package directions (about 9–11 minutes); reserve 1 cup pasta cooking water then drain the pasta.
In a large skillet over medium heat, add 1 tablespoon butter and 1 tablespoon olive oil; let the butter melt.
Add the minced garlic and 1 teaspoon Italian seasoning and cook, stirring, until fragrant, about 30 seconds.
Slowly whisk in 3/4 cup heavy cream, bring to a low simmer, then reduce heat to medium-low and cook, stirring often, until slightly thickened, about 2–4 minutes.
Stir in 1/2 cup grated Parmesan, 1/2 teaspoon kosher salt, and 1/2 to 1 teaspoon black pepper until the cheese melts into the sauce.
Add the drained pasta and 1/4 cup reserved pasta water to the skillet and toss to coat; cook over medium heat, stirring constantly, until the sauce is creamy and coats the pasta, adding more reserved pasta water 1 tablespoon at a time if the sauce is too thick.
Remove from heat and let sit 1–2 minutes before serving; serve with additional Parmesan and minced parsley if desired.
