Mix cajun seasoning into a small bowl.
Blot shrimp dry with paper towel.
Sprinkle cajun seasoning onto both sides of shrimp and set shrimp aside. Sprinkle any remaining cajun seasoning on vegetables.
Heat tablespoon of vegetable oil in Dutch Oven or large pot on high heat and sear shrimp on both sides. Set aside cooked shrimp into a bowl.
In the same Dutch oven on medium heat, add an additional tablespoon of vegetable oil.
Add onion, celery and green pepper and cook until tender.
Add ½ cup of cream to vegetables and cook until combined. Move cooked vegetables into a bowl and set aside.
In the same Dutch oven, add polenta cubes and chicken broth with Dutch Oven lid on, until the polenta becomes soft about 15 minutes. Stir until polenta softens.
Add whipping cream to polenta mixture. Add salt and pepper to taste.
Add additional water for more desired consistency.
In serving dishes, spoon generous helping of polenta and top with vegetables and shrimp.