Split langoustines down the middle and clean, removing the digestive tract that runs along the length of the langoustine.
Mix the butter, lemon juice and garlic together to make a garlic butter and brush over the langoustines.
Place the langoustines under a hot grill for 4-5 minutes or until just cooked.
Place on the plate and pour over the rest of the melted butter from the tray. Serve with lemon and chopped parsley.