Season the Steaks: Pat the steaks dry with paper towels. Season generously with salt and pepper on both sides.
Cook the Steaks: Heat olive oil in a cast iron skillet over medium-high heat. Once hot, add the steaks and sear for 3-4 minutes on each side for medium-rare. For desired doneness, adjust cooking time.
Rest the Steaks: Remove the steaks from the skillet and let them rest while you prepare the sauce.
Prepare the Shrimp: In the same skillet, add butter and let it melt. Add shrimp and cook for 2-3 minutes on each side until pink and opaque. Remove shrimp and set aside.
Make the Cajun Sauce: In the same skillet, add garlic powder, onion powder, paprika, and Cajun seasoning. Stir well, then pour in the heavy cream and lemon juice. Let it simmer for 2-3 minutes until thickened.
Combine the Shrimp: Return the cooked shrimp to the skillet with the sauce and toss to coat evenly. Simmer for an additional minute to heat through.
Serve: Place the steaks on plates and spoon the creamy Cajun shrimp sauce over them. Garnish with fresh parsley and serve immediately.