In a large Dutch oven or stockpot melt 4 tablespoons of butter. Slowly add the flour and whisk to combine. Cook the flour and butter mixture for about 10 minutes stirring regularly until the roux turns golden brown.
Add the onion, celery, bell peppers to the roux and cook until tender, about 10 minutes.
Add the garlic and cook another minute or so. Add the Cajun seasoning, smoked paprika, and can of tomatoes and stir to coat. Add the seafood broth and bay leaves and stir to incorporate. Reduce the heat to low and simmer for 20 minutes until the vegetables are tender.
Meanwhile, drizzle the shrimp with olive oil and sprinkle with 1/2 teaspoon Cajun seasoning. Toss to coat.
Add the shrimp to the hot liquid and cook for 5 to 6 minutes. Alternatively, you can cook the shrimp in a hot skillet for 3 minutes on each side and add it to the stew after it's cooked. Whatever you prefer, just don't overcook the shrimp.
Place white rice in the center of a bowl, ladle the etouffee stew and shrimp around the rice. Garnish with fresh parsley and chopped green onions.
Serve with lemon wedges.