In a small bowl, combine kosher salt, Old Bay seasoning, dried thyme, smoked paprika, and cayenne pepper to create a flavorful blackening mixture. Drizzle in 2 tablespoons of neutral oil and mix well. Rub this aromatic blend generously over the salmon fillets, allowing them to rest for about 10 minutes to soak in the spices.

Heat a large skillet over medium heat and add the remaining oil. Once shimmering, place the seasoned salmon fillets in the skillet. Sear for 3-4 minutes on each side until they develop a crispy, blackened exterior while remaining tender inside. Add halved lemon pieces to the pan with the salmon, allowing them to char slightly.

After removing the salmon and charred lemons from the skillet, add the raw shrimp and a tablespoon of unsalted butter. Season lightly with salt and pepper. Cook the shrimp for about 2-3 minutes, turning them occasionally until they are lightly browned and start to curl but are still slightly undercooked, then remove them from the pan.

Pour white wine into the same skillet, scraping the bottom to release any delicious browned bits stuck to the pan. Let it simmer for 2 minutes to reduce slightly. Stir in heavy cream, mixing well to create a rich, velvety sauce.

Return the shrimp to the skillet, allowing them to mingle with the creamy sauce. Cook together for another 5 minutes, ensuring the shrimp are cooked through and golden. Incorporate the juice from half of the charred lemon.

Plate the grilled blackened salmon and generously spoon the shrimp cream sauce over each fillet. Garnish with chopped parsley and serve with additional lemon wedges.