Heat olive oil in a large heavy-bottomed pot over medium heat. Add the sliced kielbasa and cook, stirring occasionally, until browned on both sides, about 5 minutes. Remove the kielbasa with a slotted spoon and set it aside.

In the same pot, add the chopped onion, minced garlic, and sliced bell pepper. Sauté over medium heat until the vegetables are softened and fragrant.

Stir in the Italian seasoning, chicken broth, and uncooked pasta. Bring the mixture to a boil, then reduce the heat and let it simmer uncovered. Cook until the pasta is al dente and most of the liquid is absorbed, about 10–12 minutes.

Mix in the halved cherry tomatoes, fresh spinach, and the reserved browned kielbasa. Continue to cook for 2–3 minutes, allowing the spinach to wilt and the flavors to meld.

Adjust the seasoning with salt and freshly ground black pepper to taste. Sprinkle generously with grated Parmesan cheese before serving.