Preheat your oven to 400°F degrees. Grab an 8×8-inch or 9×9-inch baking pan and rub the inside with olive oil to prevent sticking.
In a large pan over medium-high heat, add 2 tablespoons of olive oil. Once hot, add the onions, garlic, and Cajun seasoning. Sauté for about one minute until the onions are lightly golden brown and the garlic is fragrant.
Next, add the cauliflower florets to the pan. Stir them well, ensuring that each piece is coated in the aromatic mixture. The cauliflower should start to soften slightly, about 5 minutes.
Now it’s time to add the cans of whole tomatoes, chicken broth, tomato paste, and bay leaves. Stir everything together until well mixed. Bring the mixture to a rapid boil, then reduce the heat to medium. Cover and allow it to simmer for about 15 to 18 minutes until the cauliflower is fork-tender.
After simmering, uncover the pan and increase the heat to high. Allow the mixture to boil until most of the liquid evaporates, approximately 8 to 9 minutes. Make sure to stir frequently to prevent it from burning.
Transfer the mixture to a large food processor and blend until smooth and creamy. Once blended, scrape the mixture into a large bowl and place it in the freezer for a few minutes to chill while you prepare the sausage.
During this time, heat a large nonstick pan over medium-high heat. Add the sliced andouille sausage and cook until golden brown, flipping once. This should take about 1 to 2 minutes per side. Transfer the sausage to a paper towel-lined plate to absorb the excess grease.
Once the cauliflower mixture has cooled slightly, take it out of the freezer. Stir in the cooked sausage, red peppers, shredded chicken, shrimp, celery, salt, and pepper. Mix well until all the ingredients are combined.
In a separate small bowl, lightly beat the whole egg and egg white. Add the beaten eggs to the cauliflower mixture and stir until evenly incorporated.
Press the mixture into the prepared baking pan and spread it out evenly. Cover the pan with foil and bake for 20 minutes. After that, uncover and bake for an additional 25 to 30 minutes, until the top is lightly browned and the casserole is heated through.
Once done, let the casserole cool for about 10 minutes. Garnish with parsley and green onion before serving immediately. Enjoy!
