In a mixing bowl, combine shrimp with Cajun seasoning, smoked paprika, and optional cayenne pepper. Let marinate for about 10-15 minutes.

Heat a skillet over medium heat with unsalted butter and olive oil. Add onion, bell pepper, and celery; sauté for 5-7 minutes until softened. Stir in garlic and cook for an additional 30 seconds.

Stir in tomato paste, smoked paprika, cayenne pepper, dried thyme, and oregano. Gradually add chicken/seafood stock and Worcestershire sauce. Simmer for 5-7 minutes until slightly thickened.

In a separate skillet, heat olive oil over medium-high heat. Cook marinated shrimp for 2-3 minutes on each side until they turn pink and opaque.

Transfer shrimp to the simmering sauce. Warm through for 1-2 minutes and serve hot over rice, grits, or bread, garnished with parsley and lemon wedges.