In a medium bowl, toss the large shrimp with Cajun seasoning, smoked paprika, and cayenne pepper until evenly coated. Allow to marinate for about 15 to 20 minutes.

In a large skillet, heat 2 tablespoons of unsalted butter and 1 tablespoon of olive oil over medium heat. Add chopped onion, diced green bell pepper, and sliced celery. Sauté for 5-7 minutes until softened, then add minced garlic and sauté for another 30 seconds.

Stir in 2 tablespoons of tomato paste and cook for 1-2 minutes, then pour in the stock and add Worcestershire sauce, thyme, and oregano. Bring to a simmer and cook for 5-7 minutes until thickened.

In a separate skillet, heat another tablespoon of olive oil over medium-high heat. Add the marinated shrimp in a single layer, searing for 2-3 minutes on each side until pink and opaque.

Add the cooked shrimp to the simmering sauce. Simmer for 1-2 minutes, then serve over rice, grits, or bread, garnished with parsley and lemon wedges.