In a large bowl, toss the peeled and deveined shrimp with Cajun seasoning. Let marinate for about 15 minutes.

Heat a skillet over medium heat and add the unsalted butter and olive oil. Once melted, add the onion, bell pepper, and celery. Sauté for 5-7 minutes until softened. Add garlic and cook for an additional 30 seconds.

Stir in the tomato paste with the sautéed vegetables and cook for 1-2 minutes. Then, add Worcestershire sauce, chicken or seafood stock, thyme, and oregano. Let simmer for about 5-7 minutes until sauce thickens.

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

Add the cooked shrimp to the sauce in the first skillet. Stir gently and let simmer together for an additional 1-2 minutes.

Serve the shrimp and sauce over cooked rice, grits, or bread. Garnish with parsley and serve with lemon wedges.