Heat a large skillet over medium high heat and add the olive oil. Add the sausage to the skillet and cook until browned.
Add in the garlic, onion, Cajun spice, salt and pepper and sauté for 2 minutes.
Add in the bell pepper and celery and continue to sauté for another 4-5 minutes or until the vegetables are just tender.
Add the fire roasted tomatoes, rice and broth and stir well. Cover and bring to a boil over medium heat. Once boiling, turn the heat down and simmer for 20 minutes or until the rice is tender.
Take lid off and stir in the spinach until wilted.
Add in the cream, milk, Parmesan cheese and mozzarella cheese and stir well, simmering for another 2-3 minutes or until the sauce becomes creamy. Make sure to stir continuously so the rice doesn't stick to the bottom of the skillet.
Remove from the heat and garnish with green onion and cheese.