In a Dutch oven or large skillet, heat the oil over medium-high heat. Add the pork sausage and cook undisturbed for 2 minutes. Flip the pork using a spatula, season with salt and pepper, and continue to cook undisturbed for another 2 minutes. Stir and break the pork into large crumbles with a wooden spoon, cooking for an additional 1 minute. Remove the sausage with a slotted spoon to a paper towel-lined plate and set aside.

Add the andouille sausage to the same pan. Cook undisturbed for 2 minutes. Stir occasionally until the andouille is well caramelized, about 2 more minutes. Remove the andouille with a slotted spoon to a separate paper towel-lined plate and set aside.

Reduce the heat to medium. Add the bell peppers, onion, and celery to the pan. Cook, stirring occasionally, until the vegetables are softened, about 6-8 minutes. Add the garlic, Cajun seasoning, and cayenne. Season with ½ teaspoon of salt and ¼ teaspoon of pepper. Cook until fragrant, about 30 seconds to 1 minute.

Return the pork sausage to the pan. Add the rice, broth, and bay leaf (if using). Stir everything together, gently scraping any brown bits from the bottom of the pan.

Bring the mixture to a boil over medium-high heat, then immediately reduce the heat to maintain a simmer. Cover the pan and simmer for 20-22 minutes, or until the rice is cooked and tender.

Remove the pan from heat and let it sit, covered, for 5 minutes. Remove the cover and discard the bay leaf. Fluff the rice with a fork and stir in the andouille sausage. Adjust seasoning with salt and pepper if needed.

Scatter chopped green onions and parsley over the top of the dirty rice. Serve immediately and enjoy!