Prep the chicken: Pat the chicken dry. Season both sides with Italian seasoning, 1 teaspoon salt, and 1/2 teaspoon pepper. If the breasts are thick, gently pound them to about 1/2-inch even thickness so they cook evenly.

Cook the pasta: Bring a large pot of salted water to a boil. Cook the fettuccine according to package directions until al dente. Reserve 1 cup of pasta water, then drain.

Sear the chicken: Heat the olive oil in a large skillet over medium-high heat. Add the chicken and cook 4–6 minutes per side, until golden and cooked through (internal temp 165°F). Transfer to a plate, rest for 5 minutes, then slice.

Start the sauce: In the same skillet, reduce the heat to medium and add the butter. When melted, add the minced garlic. Cook 30–60 seconds until fragrant, stirring so it doesn’t brown.

Add the cream: Pour in the heavy cream. Bring to a gentle simmer and cook 3–4 minutes, stirring often, until slightly thickened. Keep the heat low to prevent scorching.

Melt in the cheese: Lower the heat to medium-low. Add the Parmesan (and Pecorino Romano if using) a handful at a time, whisking until smooth. Season with a pinch of salt, black pepper, and a tiny pinch of nutmeg.

Adjust the texture: If the sauce feels too thick, add a splash of reserved pasta water. You want it silky and able to coat the pasta without clumping.

Combine: Add the cooked pasta to the skillet and toss until well coated. Fold in the sliced chicken or arrange it on top.

Finish and serve: Taste and adjust seasoning. A squeeze of lemon can brighten the richness. Garnish with chopped parsley and extra Parmesan. Serve immediately.