Green Valley Spice Shop, Marble Arch: Open 8am to Midnight

Green Valley, at 36-37 Upper Berkeley Street, London W1H 5QF, is a Lebanese food hall that opens from 8am to midnight seven days a week, 365 days a year, including the holiday period. If you typed spice shop near me anywhere around Marble Arch or Edgware Road, this is the address that solves a late-evening shortage of za'atar, sumac or seven-spice, because almost nothing else in central London sells Middle Eastern spices that late.

Green Valley was established in 1986 and, by its own account, began trading out of a small shop of about 800 square feet on the same premises it occupies today. Determination and hard work, the shop says, took it to nearly 5,000 square feet, and the business now imports, wholesales and caters for London hotels, casinos and clubs as well as running the shop floor. It calls itself the largest and best-stocked Lebanese foodhall in London, and walking the aisles you understand the claim.

The building is split into departments that the website lists one by one: delicatessen, butcher, sweets and patisserie, creamery and juices, grocery, roastery, frozen food and catering. The spices sit in the grocery section, which also carries fresh herbs flown in from Lebanon, sacks of pulses and barrels of olives. A review quoted on the official grocery page says the shop sells seemingly every herb and spice known, and that is close to how it feels on a first visit.

Start with the Lebanese basics that the grocery page names: za'atar, sumac and the 7 mixed spices blend that Lebanese cooks call baharat. Za'atar is the thyme, sesame and sumac mix for flatbread and labneh; sumac on its own is the tart red powder that goes over fattoush and grilled onions; and seven-spice is the warm blend of allspice, pepper and cinnamon that seasons kibbeh and rice. Buy all three and you can cook most of a mezze spread at home.

Green Valley also stocks dish-specific mixes that are hard to find elsewhere in central London: kibbeh spices, falafel spices, shawarma spices, sojok spices for the spicy Armenian-Lebanese sausage, kafta spices for minced lamb skewers and the Lebanese mix for makanek sausages. These blends take the guesswork out of a recipe, so they suit cooks who want the taste of an Edgware Road grill without building a mix from twelve separate jars. Pick one dish and buy its blend, rather than all six.

Single spices are here too. The grocery list includes cardamom seeds and powder, dill seeds, nutmeg seeds and powder, coriander seeds, lime powder, curry powder, sage, rose petals, and whole and ground cinnamon. Rose petals are worth a look if you bake: crushed over a rice pudding or a pistachio cake they give the perfumed finish of a Beirut sweet shop. Lime powder brings the sour note of dried black lime to stews without the hard shell.

Do not leave without stopping at the roastery counter. Green Valley roasts nuts and seeds from the Lebanese Al-Rifai roastery and grinds coffee to order, including Lebanese-style coffee blended with or without cardamom and Arabic coffee with or without cardamom. Ask for it ground fine for a rakweh pot. You can also buy cardamom and cardamom powder here separately, so you control how strongly scented your coffee will be, plus packs of Alrifai, Najjar and Maatouk coffee.

The roastery is also where most first-timers overspend. Roasted pistachios, red melon seeds and warm spiced nuts are hard to resist, and they add up quickly by weight. A sensible plan is to choose the coffee and one bag of nuts, and treat the rest of the counter as something to come back for. If you are buying for a party, the shop also takes catering orders for ready marinated meats and mezze, which saves cooking altogether.

Because Green Valley trades until midnight, the late evening is busy with families stocking up after dinner on Edgware Road, especially in summer and during Ramadan, when the shop prepares special Lebanese sweets, dates and ready-to-eat dishes. Weekday mornings after 8am are quieter, and staff at the deli have more time to explain a spice blend. If you only need spices and coffee, head straight for the grocery and roastery and skip the long queue at the hot food bar.

Shoppers range from home cooks who know exactly which olive barrel they want, to visitors from the Marble Arch hotels who wander in for baklava; a cookery school quoted on the shop's own site calls it an authentic Lebanese cave of delights. It is fine to ask staff for help; describe the dish you plan to cook and they will point you to the right blend. Payment by card is accepted, according to reviewers on Yelp, which is not a given among the older grocers on this side of Edgware Road.

Green Valley is not a curated boutique with tasting jars and recipe cards. It is a busy working food hall, and the spice range rewards people who already know what they want. If you need guidance through hundreds of unfamiliar blends, a dedicated spice shop will suit you better. But for Lebanese and Middle Eastern cooking, nowhere in central London combines spices, fresh herbs, butcher, bakery and coffee under one roof, open until midnight every single day of the year.

Upper Berkeley Street runs a few minutes from Marble Arch station, so pair your shopping with a walk. Start at Marble Arch itself and Speakers' Corner on the north-east tip of Hyde Park, then walk up Edgware Road, the long street of Lebanese, Syrian and Iraqi cafes, shisha terraces and juice bars that gives the area its nickname, Little Beirut. Compare the sweets in the windows with what you saw at the Green Valley patisserie counter.

If you would rather stay quiet, walk west instead through Connaught Village, a small pocket of independent shops and cafes around Connaught Street, then return to Hyde Park for a bench by the Serpentine. The full loop takes about an hour at an easy pace. Carry your spices in a sealed bag in hot weather, as sumac and za'atar pick up humidity and clump if they sit in a warm rucksack too long.

Address: 36-37 Upper Berkeley Street, Marble Arch, London W1H 5QF. Phone: 020 7402 7385. Opening times on the official site: 8am to midnight, 7 days a week, 365 days a year, including the holiday period. Nearest Tube stations listed by the shop: Marble Arch and Edgware Road. Green Valley also runs delivery across London with its own drivers and vans; call the shop for details. A second branch trades as Green Valley Kensington on Kensington High Street.