Fill a large pot with water, add a pinch of salt, and bring it to a boil. Add 8 oz of penne pasta and cook according to package instructions until al dente. Reserve about ½ cup of pasta water before draining the pasta in a colander. Set the pasta aside.
Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Add the sliced chicken andouille sausage and cook until browned and slightly crispy, about 5-6 minutes. Remove the sausage from the skillet and set aside.
In the same skillet, add the diced onion, red bell pepper, and green bell pepper. Sauté for 4-5 minutes until the vegetables are softened and fragrant. Add the minced garlic and cook for an additional 1 minute, stirring frequently to avoid burning.
Pour in the can of diced tomatoes (with juices) and stir to combine. Sprinkle in 2 teaspoons of Cajun seasoning, and season with salt and pepper to taste. Let the tomato mixture simmer for 5 minutes to meld the flavors.
Reduce the heat to medium-low and slowly stir in 1 cup of heavy cream, allowing the sauce to thicken slightly. Return the cooked sausage to the skillet and stir to coat everything evenly.
Add the cooked penne pasta to the skillet and gently toss everything together. If the sauce is too thick, add a splash of the reserved pasta water to loosen it up and help the sauce cling to the pasta.
Remove the skillet from heat. Sprinkle freshly chopped parsley over the top for a burst of color and freshness. Serve immediately with a side of crusty bread or a simple green salad.