Flounder has got to be my favorite fish - delicate and delicious it deserves to be on the same pedestal as the whitebait.
I remember - when hitchhiking once - a Maori bloke telling me that snapper was shit fish - he just ate flounder - yellow belly flounder at that. He was specific - others not so. After drag netting on Waikanae beach once I ended up with half a dozen sole - which impressed an average Kiwi bloke. I told them that they were 'sole' - he just said 'they're all flounder though - in't they!'.
Here are some pictures of New Zealand flatfish to help:
This is a Yellow Belly flounder - it has a yellow blotchy belly - indeed! It is the best tasting of the flounder - normally caught netting or spearing in a river or estuary.
The Sand Flounder is more 'angular' in shape - and has a white belly. Normally these are caught drag netting in the sea. These are best - when really big. Pan fry - the meat has a lovely gelatinous texture.
The Black Flounder - is well black with red blotches. It has a grey green belly. Normally you see these up a river. They can grow very large - and look beautiful. However, I don't spear these - their flesh is a little bitter - and the meet often green around the bones!
This (is not a very good picture) - of the common sole. It is slightly green in color and has a round head. I catch these drag netting in the sea. Only keep the big ones - the little ones are very skinny!
The Turbot - is like a really large sole - but with a pinkish stomach. I catch these drag netting (once in a while). It is a buzz to get one of these - because of the large size - and the delicious taste.
There is also the Lemon Sole - but I have not caught these so left out.
Look there are two established methods for cooking Flounder - whole or filleted.
If I catch half a dozen or more - I fillet - lightly flour and fry in butter - and serve with a pinch of Maldon Sea Salt and a squeeze of fresh lemon.
If I only catch a couple - I'll pan fry whole - and make a garlic lemon sauce.
Either way - they are my favorite seafood.
Also - don't ever buy frozen flounder - yuk - what a waste of good fish!