- Preheat oven to 400° F (200° C).
- Rinse salmon, and arrange in a 9x13 inch baking dish.
- Sprinkle salt, pepper, onion powder, and dill over the fish.
- Place pieces of butter evenly over the fish, if used.
- Bake in preheated oven for 20 to 25 minutes. Salmon is done when it flakes easily with a fork.