To create the delicious One Pot Chicken Pasta, follow these straightforward steps:

1. Heat Oil: In a large pot, heat the olive oil over medium heat.
2. Cook Chicken: Add the diced chicken, seasoning with salt and pepper. Cook for about 5-7 minutes until browned and cooked through. Remove the chicken and set it aside.
3. Sauté Vegetables: In the same pot, add chopped onion and minced garlic. Sauté for 2-3 minutes until fragrant and translucent.
4. Add Broth and Tomatoes: Pour in the chicken broth and diced tomatoes, stirring to combine.
5. Incorporate Pasta: Add the penne pasta and Italian seasoning, stirring to ensure all pasta is covered with the liquid.
6. Simmer: Bring the mixture to a boil, then reduce heat to low. Cover and simmer for about 15 minutes, or until the pasta is al dente and the liquid has mostly absorbed.
7. Add Cream and Spinach: Stir in the heavy cream and spinach leaves. Mix well and cook for an additional 3-5 minutes until spinach wilts.
8. Return Chicken: Add the cooked chicken back into the pot, mixing everything evenly.
9. Taste and Adjust: Check the seasoning and adjust with more salt, pepper, or Italian seasoning if needed.
10. Serve: Garnish with grated Parmesan cheese and fresh basil leaves before serving.