Lovely turbot is a king among flatfish. It's rare to see it whole on the fishmonger's slab but you can't miss its distinctive elong- ated diamond shape, fringed with a skirt of comparatively long fins, Jagger lips and eyes lined up on one side of its little head.

Although the breeding season runs officially between April and August, there were plenty of these handsome fish last Tuesday at the disarmingly quiet, impressively run electronic fish market in Looe.

There's no quota on turbot at Looe but inshore fishermen who catch them around this part of the south Cornwall coast have a voluntary agreement not to land fish below 30cm. Amazingly you can go online (www.looe-fish-selling.co.uk/electronic_auction.htm) and see exactly what has been landed, by whom and in what boat, and if you buy Cornish tagged fish, it is entirely traceable.

Glancing round the heavily iced boxes, I saw a heartening range of fish caught the previous night by a dozen boats. Huge pale cod, plump pollack with big black eyes, whiting and coley lay next to box after box of enormous conger eels, curled up like my sons' lurcher, with faces almost as angelic.

All the familiar oily fish were in abundance, herrings, pilchards and mackerel, the peacock among this undervalued, sustainable fish family. I was tempted by Dover and megrim sole but had one of those eureka moments when I got chatting to Angie Pengelly, the only female bidder at the market. She is descended from a long line of Looe fishermen and boat owners, and took over the family fish shop with her sister Jackie and sister-in-law Sheena eight years ago.

I saw turbot ranging from 2kg up to 6kg, although it can grow to 25kg, about 1m in length, but with Angie's help, chose an exceptionally fine 1.8kg turbot. Angie took it off to gut and pack at her small but brilliantly stocked shop, Pengelly's, a stone's throw from the market.

I headed back to London with everything I needed for my fish dinner from Angie's shop; Cornish new potatoes, cucumber, farm eggs and new-season garlic for the sauce, and a big pot of Cornish sea salt (www.cornishseasalt.co.uk), which turned out not to be suitable for baking the fish in.

It takes nerve and a lot of much coarser rock salt for this desperately simple, very impressive cooking method. The salt sets hard and the fish steams evenly and very quickly, ending up perfectly seasoned.

The pearly white flesh, with its dense yet delicate texture, slides off the bone in pleasingly silky flakes and is delicious with mild aioli, just garlicky enough to be noticeable but not enough to swamp the turbot and new potatoes.

All recipes serve 6.

Turbot in a salt crust

Gentle aioli

Cucumber and minted peas

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