Heat olive oil in a large deep skillet or Dutch oven over medium heat.
Add sliced kielbasa sausage to the skillet and cook for 4 to 5 minutes, stirring occasionally, until browned. Remove sausage from skillet and set aside.
In the same skillet, add diced onion and cook for 3 to 4 minutes until softened.
Add minced garlic and cook for 1 minute until fragrant.
Pour in diced tomatoes with their juice, chicken broth, and add uncooked penne pasta.
Stir in dried Italian seasoning, crushed red pepper flakes, salt, and black pepper.
Bring the mixture to a boil, then reduce heat to medium-low and cover the skillet.
Simmer for 12 to 15 minutes, stirring occasionally, until the pasta is tender and most of the liquid is absorbed.
Return the browned kielbasa to the skillet and stir in heavy cream.
Cook for an additional 2 to 3 minutes until heated through and sauce is creamy.
Remove from heat and stir in shredded Parmesan cheese until melted and combined.
Garnish with chopped fresh parsley before serving.