Why a po'boy belongs on a British table

British oysters have a long history. Romans shipped them inland, Victorians ate them with stout, and today you will find them at Whitstable, Mersea Island, Carlingford, Loch Fyne and the Helford. Our native oyster, Ostrea edulis, is prized and slow-growing, available in months with an r. The Pacific rock oyster is more plentiful, grown from Cornwall to Scotland, and it fries beautifully. A po'boy, that Louisiana classic, is simply a soft roll stuffed with crisp fried oysters and sharp slaw. It suits our coastal seafood culture: messy, generous, best eaten with your elbows on a harbour wall. This is a practical recipe, built for British oysters and appetites.

Choosing and preparing your oysters

Ask your fishmonger to shuck the oysters for you. They will open them, keep the liquor, and hand you a tub ready to fry. If you shuck at home, use a tea towel to hold the shell, find the hinge, and twist. Keep the oysters in their liquor in a bowl over ice. You want 12 to 16 medium oysters. Pacific rock oysters are easier to handle and have a meaty texture that stands up to frying. Natives are smaller and more delicate, so fry them for a shorter time. Pick out any bits of shell. Just before coating, drain the oysters and pat them dry on kitchen paper. Reserve the liquor for the slaw dressing or a bloody mary.

• 12–16 shucked oysters, liquor reserved
• A bowl of ice to keep them cold
• Tea towel and oyster knife if shucking yourself

The coating that crisps and clings

Fine cornmeal, not polenta or coarse grits, is the key. In a wide bowl, mix 100g fine cornmeal, 50g plain flour, 1 teaspoon fine salt, 1 teaspoon smoked paprika, half a teaspoon cayenne pepper, half a teaspoon garlic powder and plenty of black pepper. In a second bowl, pour 200ml buttermilk. If you cannot find buttermilk, stir a tablespoon of lemon juice into 200ml whole milk and leave for ten minutes. Add a tablespoon of hot sauce and a teaspoon of Dijon mustard to the buttermilk. Dip each oyster in the buttermilk, then press it into the cornmeal mixture. Set the coated oysters on a rack for five minutes. This rest helps the coating stick. One layer is enough for a shatteringly crisp shell.

Frying for golden crunch

Use groundnut or rapeseed oil, about 5cm deep in a heavy saucepan. Heat it to 180C. No thermometer? A cube of bread should turn golden in 30 seconds. Fry the oysters in batches of four or five. Do not crowd the pan, or the temperature drops and the coating turns greasy. Fry for two to three minutes, turning once, until deep golden brown. Lift them out with a slotted spoon and drain on a wire rack, not kitchen paper, which steams the crust. Sprinkle with flaky salt straight away. Keep cooked oysters in a low oven at 100C while you fry the rest, but really, they are best eaten within ten minutes. Test one oyster first to check seasoning and oil temperature.

Tangy slaw that cuts through the fry

The slaw must be sharp, not sweet and creamy. Shred a quarter of a white cabbage and a quarter of a red cabbage as finely as you can. Grate one large carrot. Slice half a red onion thinly and rinse it under cold water to take away the harshness. Put the vegetables in a colander, sprinkle with a teaspoon of salt, and leave for ten minutes. Squeeze out the water with your hands. For the dressing, whisk three tablespoons of mayonnaise, one tablespoon of cider vinegar, one teaspoon of Dijon mustard, one teaspoon of caster sugar, half a teaspoon of celery salt and lots of black pepper. Toss the vegetables with the dressing. Add a tablespoon of chopped pickled gherkins or pickled jalapeños if you like. Let the slaw sit for fifteen minutes before serving.

• White and red cabbage, finely shredded
• Carrot, coarsely grated
• Red onion, thinly sliced and rinsed
• Dressing: mayonnaise, cider vinegar, Dijon, sugar, celery salt
• Optional: chopped pickles or jalapeños

Building the sandwich and serving it right

Choose soft rolls: brioche buns, milk rolls, or small baguettes. Split them and toast the cut sides in a buttered pan until golden. Spread the bottom with remoulade, or mayonnaise mixed with a little hot sauce and chopped capers. Pile on the slaw, then three or four fried oysters per roll. Squeeze over lemon juice and add a dash of hot sauce. Replace the top and press gently. Serve immediately with crisps, a few pickles and any extra slaw. Assemble just before eating so the oysters stay crisp. To drink, a dry cider from Somerset or Normandy, a glass of Muscadet, or a pale ale works beautifully. Eat them outside if you can, with salt air and a cold drink.

Oysters are not just for swallowing raw with a glug of champagne. Frying them in cornmeal is a fine way to honour a humble, sustainable catch. Use natives when they are in season, from September to April, and Pacific rock oysters for the rest of the year. Ask your fishmonger what is local. Then make a po'boy, make a mess, and enjoy the crunch.