Broadway Market Fishmonger Fin and Flounder: Sunday at 9 am

Fin and Flounder sells fish from 71 Broadway Market, Hackney, London E8 4PH, and it is shut on Mondays. The shop opens Tuesday to Friday from 10 am to 7 pm, Saturday from 10 am to 6 pm and Sunday from 9 am to 5 pm, so the Sunday morning slot is the earliest of the week.

Fin and Flounder was started by Brendan O'Sullivan, and trade press coverage in 2021 dated the launch to 2014, describing it as a staple of Broadway Market that buys fresh seafood directly from Cornish day boats. The market's own directory calls it a traditional, family-run business, and the email address for wholesale enquiries still goes to Bren.

Its reputation inside the restaurant trade is bigger than the shop. The homepage now says Fin and Flounder supplies some of London's best restaurants, and the 2021 reports named kitchens such as Brat, Rochelle Canteen, The Clove Club, Lyle's, Smoking Goat, Bright and Tacos Padre among its wholesale customers. Buying here means choosing from the same supply chain those chefs rely on, at a retail counter you can walk up to.

The wholesale side is still open to new kitchens. The homepage invites anyone who wants Fin and Flounder as a fish and seafood supplier to send Bren a message, and it publishes separate wholesale terms. For a home cook, the useful takeaway is that the retail counter shares stock with a business that has to satisfy demanding chefs every day.

The directory description is specific about sourcing. The shop has long-standing relationships with day-boat fishermen from Scotland to Cornwall, and it buys from what it calls the best merchants at Billingsgate fish market as well as suppliers in Spain and France. Time Out's listing added that the mongers follow Marine Conservation Society guidelines strictly when deciding what to stock.

Day-boat fish matters because of time. A day boat goes out and returns to harbour within the same day rather than staying at sea for a week, so its catch reaches the market in better condition than fish held in a trawler's hold. When a counter is supplied from Cornish day boats, the flesh should be firm, the eyes bright and the smell clean, which are the three things worth checking on any fish you buy here or anywhere else.

The practical result is a counter that does not look the same two weeks running. The shop says it sells the best fish, shellfish and crustaceans, plus anything unusually wonderful from the sea that comes its way on the day. If you see a species you do not recognise, that is the moment to ask, because the staff clearly enjoy explaining it.

Fin and Flounder offers to prepare what you buy to the specification of a recipe, or simply the way you like to eat your fish. That is the most useful sentence in its whole description. Arrive with the recipe on your phone, show the quantities and the cut, and the fishmonger will portion, skin or butterfly to match, saving you the trimming at home.

The shop also says in-house recipes and cooking techniques are plentiful and that its staff love to show off, so do not be afraid to ask. A good opening question is what came in that morning that they would cook themselves. A better follow-up is how long it will keep, because some shellfish are best eaten the same day while firmer white fish will sit happily until tomorrow.

One honest warning: do not plan a Monday seafood dinner around this shop. It is closed that day, and the nearest fallback is to buy on Sunday morning and keep the fish well chilled overnight. Firm fish such as monkfish or hake handles that wait better than delicate fillets or live shellfish.

Broadway Market is famous for its Saturday street market, when stalls fill the road and the pavements become crowded with shoppers and visitors from across London. The fish shop is open 10 am to 6 pm that day, but the crush outside can make a calm conversation at the counter harder, and you may be carrying fish through a busy street for a while.

Sunday is the smarter choice for a serious shop. Doors open at 9 am, an hour earlier than any other day, and the street is calmer before brunch crowds arrive. Buy first, then take your time with coffee and the park. On weekdays, the 7 pm close from Tuesday to Friday is late enough to pick up dinner on the way home from work.

The customers tend to be East London home cooks who treat the shop as their regular fishmonger, plus restaurant people who know the wholesale side. The unwritten rule is patience. If someone ahead of you has asked for a fish to be filleted and pin-boned, it will take a few minutes, and the person behind the counter is doing it properly.

Keep your order compact and specific. Say how many people you are feeding and whether you want the bones and head for stock. If you are unsure, ask for half the amount and come back, since the shop is open six days a week and fresh is always better than frozen leftovers.

The market street runs between London Fields at its southern end and the Regent's Canal at its northern end, which makes a natural loop. Walk north to the canal towpath for a stroll towards Victoria Park, or head south into London Fields, a large open park with a popular heated lido on its western side.

On a Saturday, browse the food stalls first, but leave the fish shop until last so your purchase is not sitting in a warm bag. On a Sunday, do the opposite and buy at 9 am, then walk the canal while the street is still quiet.

Address: Fin and Flounder, 71 Broadway Market, London E8 4PH. Hours: Monday closed, Tuesday to Friday 10 am to 7 pm, Saturday 10 am to 6 pm, Sunday 9 am to 5 pm. Email: info@finandflounder.com. Restaurant and wholesale enquiries go to the shop directly.

Ask the Karpo APP to build a Sunday morning in Hackney around the 9 am opening, with the canal towpath and London Fields mapped out for after you shop.