Prepare the mashed potatoes: Boil the potatoes in salted water until soft and tender, about 15–20 minutes. Drain well, then mash with butter and milk until smooth and creamy. Season with salt and pepper to taste and keep warm.

Cook the salmon: Pat salmon fillets dry and season with Cajun spice, salt, and pepper. Heat olive oil and butter in a skillet over medium-high heat. Sear salmon skin-side down for 4–5 minutes until crisp, then flip and cook another 2–3 minutes until golden and just cooked through. Remove from the pan and set aside.

Sear the shrimp: In the same pan, melt butter and add minced garlic. Sauté for about 30 seconds. Add shrimp, sprinkle with Cajun seasoning, and cook 1½–2 minutes per side until pink and lightly charred. Squeeze over a bit of lemon juice, then remove from heat.

Make the Cajun cream sauce: Using the same skillet, melt butter and sauté garlic for 30 seconds. Pour in the heavy cream and let it simmer gently for 2–3 minutes. Stir in Parmesan cheese and Cajun seasoning until the sauce turns thick and silky. Season with salt and pepper, then toss the shrimp back into the sauce to coat evenly.

Assemble the dish: Spoon a generous portion of mashed potatoes onto each plate. Place a salmon fillet on top and arrange the shrimp alongside. Drizzle with the rich Cajun cream sauce over the salmon and potatoes. Finish with chopped parsley and a dash of black pepper for a beautiful presentation.