Slice the kielbasa diagonally into 1-inch pieces. Heat 1 tablespoon of olive oil in a large Dutch oven over medium heat. Arrange the kielbasa in a single layer and sauté for approximately 2 minutes on each side until browned. Transfer the cooked kielbasa to a plate and set aside.

Add the remaining tablespoon of olive oil to the same Dutch oven. Add the diced onions, salt, and black pepper. Stir frequently and cook for about 2 minutes or until softened. Add the minced garlic and sauté for an additional 30 seconds, being careful not to burn the garlic.

Pour the chicken stock and heavy cream into the pot. Stir to combine, then add the dry penne pasta. Ensure the pasta is fully submerged in the liquid. Cover the pot with a lid and cook over medium heat for 12 minutes, stirring occasionally to prevent the pasta from sticking to the bottom.

Return the cooked kielbasa to the pot, along with the chopped roasted red peppers. Stir to incorporate the ingredients evenly. Cover the pot and allow the mixture to simmer for an additional 2 minutes, ensuring the flavors meld together.

Remove the pot from heat. Gradually add the grated Parmesan cheese, stirring continuously until the cheese is fully melted and the sauce becomes creamy and smooth.

Sprinkle freshly minced parsley over the dish before serving. Serve immediately to enjoy the dish at its best texture and flavor.