Put the salmon on a plate, skin side down, and gently pat dry.
In a small bowl, mix together paprika, ground sumac, garlic powder, onion powder, oregano, thyme, salt, and cayenne.
Drizzle 1 tablespoon of olive oil over the salmon, then massage the spice mixture onto the salmon, ensuring it's thoroughly coated.
In a large skillet, heat the remaining 1 tablespoon of olive oil over medium heat. Add the salmon fillets with the flesh side down. Let them cook without disturbance until the surface turns blackened, approximately 2-3 minutes. Carefully flip the fillets and add the butter. Continue cooking over medium heat until the skin becomes crispy and the fish flakes easily with a fork, which should take another 5-6 minutes. During this time, occasionally tilt the pan and use a spoon to drizzle the melted butter from the pan over the blackened salmon.
Transfer the salmon to serving plates, squeeze some lemon over it, and optionally, garnish with parsley.