Preheat the oven to 400°F (200°C)
Pat the haddock fillets dry
Place the fillets on a lightly greased baking sheet or in a baking dish
Brush or drizzle with olive oil or melted butter
Season with salt and black pepper
Add optional seasonings such as garlic, lemon juice, paprika, or herbs
Bake for 10 to 15 minutes, depending on thickness
Check that the fish flakes easily with a fork and is opaque throughout
Remove from the oven
Serve immediately