Make sure to pat the fish dry with a paper towel before seasoning it. This will ensure the fish browns nicely and the skin becomes crispy.To make the garlic lemon butter sauce ahead of time, prepare the sauce and store it in an airtight container in the refrigerator for up to 3 days. Reheat the sauce in a saucepan before serving.To make the recipe even simpler, the Barramundi fillets can be baked in the oven without searing them in the skillet first.