Toss the potatoes with olive oil and 1 tbsp of Cajun seasoning roast at 400 Celcius for 35 min in the oven.
Add 1 tbsp of olive oil to the pan, sauté the sausage, and remove.
Add 1 tbsp olive oil to the pan, toss shrimp with 1 tbsp cajun spice, sauté until cooked through, and remove from the pan when done.
Add the 2 tablespoons of oil to the pan. Add bell peppers, celery, jalapeño, onion, and garlic. Sauté for 6 minutes, stirring occasionally, until the onions are softened.
Add the crushed tomatoes, Cajun seasoning, cayenne, and stir to combine. Continue cooking until the mixture reaches a simmer. Then reduce the heat to medium-low, cover, and simmer for about 25-30 minutes stirring every 5 minutes or so along the way so that the rice does not burn.
Add extra Cajun seasoning if desired.
Serve over potatoes and top with green onions and parsley.