1. Bring a large pot of salted water to a boil and cook the rotini pasta according to package directions. Drain and set aside.

2. In a large skillet, heat olive oil over medium-high heat. Season the diced chicken with salt and pepper, then cook until golden brown and cooked through. Transfer chicken to a plate and set aside.

3. In the same skillet, add butter and minced garlic. Sauté for about 30 seconds until fragrant.

4. Whisk in flour and cook for 1 minute. Slowly pour in the chicken broth, whisking constantly to avoid lumps. Stir in heavy cream, Parmesan cheese, Italian seasoning, and crushed red pepper flakes. Simmer until thickened, about 3-5 minutes.

5. Return the chicken to the skillet, then add the cooked pasta. Toss to coat everything evenly in the sauce. Garnish with chopped parsley and more Parmesan if desired.