Step 1: Prepare the Chicken

Pat the chicken breasts dry with paper towels. If the breasts are thick, pound them to an even thickness using a meat mallet. Season both sides generously with salt, black pepper, Italian seasoning, and garlic powder. Set aside while you prepare the other ingredients.

Step 2: Cook the Pasta

Bring a large pot of salted water to a rolling boil. Add the rotini pasta and cook according to package directions until al dente, usually 9-11 minutes. Reserve 1 cup of pasta water before draining. Drain the pasta in a colander and set aside.

Step 3: Sear the Chicken

Heat olive oil in a large skillet over medium-high heat. Once the oil is shimmering, add the seasoned chicken breasts. Cook for 6-7 minutes on the first side without moving them, until a golden-brown crust forms. Flip and cook for an additional 5-6 minutes until the internal temperature reaches 165°F. Remove the chicken from the skillet and let it rest on a cutting board.

Step 4: Make the Garlic Butter Base

In the same skillet, reduce heat to medium and add the butter. Once melted, add the minced garlic and sauté for 1-2 minutes until fragrant and lightly golden. Be careful not to burn the garlic. Sprinkle the flour over the garlic butter and whisk continuously for 1 minute to create a roux.

Step 5: Create the Creamy Parmesan Sauce

Slowly pour in the heavy cream and milk while whisking constantly to prevent lumps. Bring the mixture to a gentle simmer and cook for 3-4 minutes, stirring frequently, until it begins to thicken. Reduce heat to low and gradually add the grated parmesan cheese, stirring until completely melted and smooth. Season with salt, black pepper, and red pepper flakes if using.

Step 6: Combine Everything

Slice the rested chicken into strips or bite-sized pieces. Add the cooked rotini to the creamy parmesan sauce and toss gently to coat every piece of pasta. If the sauce is too thick, add reserved pasta water one tablespoon at a time until you reach desired consistency. Add the sliced chicken back to the skillet and gently fold it into the pasta.

Step 7: Serve

Transfer the creamy garlic butter chicken and rotini to serving plates or a large serving bowl. Garnish with additional grated parmesan cheese and freshly chopped parsley. Serve immediately while hot.