Bring a large pot of salted water to a boil. Add 8 ounces of penne pasta and cook according to the package instructions until al dente. Drain the pasta, reserving about 1/2 cup of pasta water for later use. Set aside.
Heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Add the diced chicken breast, seasoning with salt and pepper. Cook until the chicken turns golden and is cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, reduce the heat to medium and add the minced garlic. Sauté for 1-2 minutes until fragrant and golden, making sure not to burn it.
Pour in 1 cup of heavy cream and 1 cup of chicken broth, stirring to combine. Bring the mixture to a gentle simmer, allowing it to thicken slightly, about 3-4 minutes. Stir in 1 teaspoon of Italian seasoning.
Stir in 2 cups of fresh spinach, letting it wilt into the sauce. Then add 1/2 cup of grated Parmesan cheese, stirring continuously until the cheese melts and the sauce becomes creamy.
Return the cooked chicken to the skillet and toss in the drained penne pasta. Mix everything thoroughly, adding reserved pasta water a little at a time if the sauce needs loosening. Adjust seasoning with salt and pepper to taste.
Plate your Creamy Garlic Chicken Florentine Penne immediately, garnishing with extra Parmesan or a sprinkle of fresh herbs if desired.