Preheat the oven to 400°F (200°C)
Pat cod fillets dry with paper towels
Place cod on a baking sheet or in a baking dish
Drizzle with olive oil or melted butter
Season with salt and black pepper
Add garlic, lemon juice, herbs, or spices if desired
Bake for 10 to 15 minutes, depending on thickness
Check that the cod flakes easily with a fork
Remove from the oven
Serve immediately