Mise en place. Make sure kielbasa, peppers, and onions are sliced and garlic minced.
Heat the olive oil in a large skillet over medium heat. Add the kielbasa and cook for 5-7 minutes, until lightly browned, stirring occasionally.
While cooking the kielbasa, bring a large pot of water to a boil. Salt. Cook penne according to package directions. Reserve 1 cup of pasta water before draining. Drain. Set aside.
Add the onions and bell pepper to the skillet the kielbasa is cooking in. Continue to cook for another 4-5 minutes, stirring occasionally, until peppers and onions slightly softened.
Stir in the minced garlic, Italian seasoning, and red pepper flakes. Continue to cook and stir for 1 minute.
Stir in tomato paste. Continue to cook and stir for 1-2 minutes.
Stir in crushed tomatoes and chicken broth. Bring to a boil. Lower the heat and simmer for 10 minutes, stirring occasionally.
Turn heat down to low. Stir in cooked pasta. Add the parmesan cheese and stir well. If too thick, slowly add some of the reserved pasta water, stirring until at desired consistency. Serve immediately.