Add the sliced sausage to a large skillet set over medium heat. Cook it, stirring often, until it's begun to brown. Remove the sausage to a waiting plate. Set aside.
1 lb andouille sausage
Add the chicken to the skillet, then sprinkle 2 teaspoons of the Cajun seasoning evenly out overtop. Toss it to coat.
1 lb chicken breasts, 3 tsp Cajun seasoning
Cook the chicken, stirring often, until it's all evenly cooked. Remove the chicken from the skillet to a waiting plate. Set aside.
Add the vegetables to the hot skillet. Sprinkle the remaining Cajun seasoning on top, and toss everything to coat. Let the vegetables sauté just until they've begun to become soft. Add the garlic, stir, and cook another 60 seconds.
1 green bell pepper, 1 large white onion, 4 stalks celery, 3 tsp minced garlic
Remove the skillet from heat, and stir in one jar of alfredo sauce & the half cup of water. Stir together until combined evenly. Set aside.
2 15 oz jars alfredo sauce
Lightly spray a deep 9x13" casserole dish with non stick cooking oil. Add 3 lasagna noodles to the bottom of the pan. Break up a fourth noodle to fill in any bare spots.
9-12 lasagna noodles
Spread half of the meats evenly out overtop.
Add half the veggie mixture to the dish, and gently spread it out evenly to cover the noodles/dish.
Spread half of the shredded cheese evenly out overtop. Repeat this layer once, and then top with the remaining pasta noodles.
2 cups shredded mozzarella cheese
Pour the second jar of alfredo sauce evenly out overtop of the dish, spreading as necessary. Cover the dish tightly with aluminum foil.
Bake at 350° for 1 hour and 30 minutes.
Remove the dish from the oven, and let it rest for 15 minutes before uncovering. Once uncovered let it rest another 5-10 before slicing and serving.