In a large pot or Dutch oven, heat a splash of olive oil over medium heat. Add 1 chopped onion and 2 minced garlic cloves, sautéing for about 2–3 minutes until fragrant and translucent.

Add 14 ounces of sliced smoked sausage to the pot and cook for another 4–5 minutes, stirring occasionally, until the sausage is nicely browned.

Sprinkle in 2 tablespoons of Cajun seasoning, stirring to coat the sausage evenly. Pour in 4 cups of chicken broth and 1 cup of heavy cream, bring to a simmer.

Once simmering, add 12 ounces of penne pasta to the pot, ensuring it is submerged. Cover and cook for about 10–12 minutes, stirring occasionally.

After the pasta is cooked, reduce heat to low. Stir in 1 cup of grated Parmesan cheese until melted and creamy.

Remove the pot from heat and serve hot, garnished with freshly chopped parsley if desired.