Preheat your oven to 400°F (200°C).
Lightly grease a baking dish with cooking spray or olive oil.
In a bowl, combine mayonnaise, grated Parmesan cheese, chopped parsley, garlic powder, salt, and pepper. Mix well until all ingredients are thoroughly combined.
Place the salmon fillets in the prepared baking dish, skin side down if applicable. Spread an even layer of the mayonnaise mixture over each fillet.
Bake in the preheated oven for about 15-20 minutes or until the salmon flakes easily with a fork and the topping is golden brown.
Once baked, remove from the oven and let it rest for a few minutes before serving.