The batter is made with Fursty Ferret bitter and flour. Nothing else, well, bit of salt and pepper. Just enough to make the batter easy to use (I think the term "cover the back of the spoon" is often used).
I was using a small saucepan so I chopped up the cod fillet into similar sized pieces, and cooked the fillet in two batches. It was perfectly cooked with 4-5 mins, the steam pocket created by the batter around the fish steamed the fish wonderfully.
I had a bit left over so I sliced an onion and threw it in. I put the left-over batter in the fridge for tomorrow, I have another fillet to use up. Nice and healthy after footy :-)
