Boil a large pot of salted water and cook the pasta to al dente according to the package instructions.

Season the chicken pieces with salt and pepper, then dredge them lightly in flour.

Heat the olive oil and butter in a skillet over medium-high heat. Once the pan is hot, add the chicken and cook until the exterior is no longer pink. Remove the chicken from the skillet and set it aside.

Take the skillet off the heat. Stir in the garlic, chicken broth, lemon juice, Dijon mustard, and Italian seasoning. Return the skillet to the heat and let the mixture bubble for about a minute, scraping up any flavorful bits from the bottom of the pan.

Add the cooked chicken, heavy cream, and spinach to the skillet. Cook for approximately 5 minutes, ensuring the chicken is thoroughly cooked and the spinach wilts. Lower the heat if the sauce thickens too quickly or begins bubbling excessively.

Drain the pasta and combine it with the sauce in the skillet. Stir in the freshly grated Parmesan cheese. Taste and adjust the seasoning with additional salt and pepper if needed.