An interesting phenomenon occurs when a long-standing restaurant continuously accommodates the requests of its most loyal — or sometimes, pickiest — patrons over decades of operation. Hospitality becomes top priority, and substitutions and modifications are politely accepted. Out of all this, a collection of off-menu items and modifications emerge. Some might call it a “secret” menu; regulars just call it a standard order.

La Taqueria and House of Prime Rib are great examples of this evolution. Each of these San Francisco restaurants has been around for decades, generating generations of regulars who want it their way.

At some point down the line, one customer decided that she wanted her La Taqueria burrito grilled to a perfect golden crisp on the plancha, or a House of Prime Rib King Henry Cut done in the English style — and in both cases, the operators generously delivered. The happy customer soon returns, orders the same thing the same way, another customer sees it, wants it, orders it and so on and so forth until it becomes a “thing” to those in the know. Finally, some nosy, food-obsessed writer comes along and sniffs out the different dishes, and after much prying and prodding with the owners, is able to tease out a slew of mind-blowing modifications into a list of “secret menu items.”

Swan Oyster Depot, like La Taqueria and House of Prime Rib, is an essential institution in San Francisco. This holy church of fresh seafood, this bastion of deliciousness, needs no introduction. The 18-seat counter has been around for more than 100 years and is beloved by locals and tourists alike. Anthony Bourdain visits every time he comes to San Francisco, and Lucky Peach half-jokingly calls it “the best place to eat in America.”

The greatest hits of the restaurant are clearly written on the massive menu board — chowder, Louie salads, seafood cocktails, fresh oysters and so on — but as at La Taqueria or House of Prime Rib, there’s more to ordering than what’s listed on the bill of fare.

So much of the charm of Swan Oyster Depot comes from the Sancimino brothers, who own the place, and their staff. As such, the menu is full of sneaky, little tidbits that are illuminated only through conversation and frequency of visits.

Take, for example, the olive oil and vinegar dressing. Technically this is on the menu as an option to go with your salad, yet it is often overlooked because clearly Louie dressing is always a good move with seafood salads — right? But it’s what’s not written on the menu that’s important. Swan makes its olive oil vinaigrette with equal parts Dijon mustard and crab fat as the emulsifiers. Crab. Fat. If they simply called it crab-fat dressing, it would fly off the shelf. But now you know.

Of course, there are bigger “secrets” to be had, customizations for regulars over years of business that have stuck; after all, the Sancimino brothers are just too nice for there not to be. But remember: The real secret lies within Swan Oyster Depot’s ability to provide decades of unconditional hospitality.

Sicilian Sashimi

The Sicilian sashimi is more of an open secret — everyone knows about it. But it’s also not on the menu, so there you go. Thinly sliced raw salmon, tuna and scallops are served simply with a drizzle of olive oil, freshly cracked black pepper and some capers on top. Squeeze a bit of lemon for some acid, and you’ve got a classic off-menu hit.

The Maverick

There's a regular who visits about once a week. He pulls up in a Bentley and orders a plate to-go that's piled high with a pound of crab, a filet of smoked trout and exactly 4 prawns. The plate ends up costing between $75-$90 and is appropriately referred to among the Swan family as The Maverick. Supposedly the maverick behind The Maverick made his money in construction.

Back to Gallery At Swan Oyster Depot, a secret menu built for regulars 17 1 of 17 Photo: John Storey, Special to the Chronicle 2 of 17 Photo: John Storey, Special to the Chronicle 3 of 17 Photo: John Storey, Special to the Chronicle 4 of 17 Photo: John Storey, Special to the Chronicle 5 of 17 Photo: John Storey, Special to the Chronicle 6 of 17 Photo: John Storey, Special to the Chronicle 7 of 17 Photo: John Storey, Special to the Chronicle 8 of 17 Photo: John Storey, Special to the Chronicle 9 of 17 Photo: John Storey, Special to the Chronicle 10 of 17 Photo: John Storey, Special to the Chronicle 11 of 17 Photo: John Storey, Special to the Chronicle 12 of 17 Photo: John Storey / Special to The Chronicle 2016 13 of 17 Photo: John Storey, Special to the Chronicle 14 of 17 Photo: John Storey, Special to the Chronicle 15 of 17 Photo: John Storey, Special to the Chronicle 16 of 17 Photo: John Storey, Special to the Chronicle 17 of 17 Photo: John Storey / Special to the Chronicle

































Crabsanthemum

Everyone knows the crab legs are the best part of the crab — the fat, tender, sweet little morsels of deliciousness are the first items to go on every combination plate ever shared. But fight no more and order a crabsanthemum: Crab legs, and only crab legs, are delicately arranged in a flower-like pattern on a plate and served with a side of Louie sauce.

A Dozen Eggs

Ask for a “dozen eggs” and you’ll get a plate of thinly sliced raw scallops dotted with Sriracha that swim in a shallow pool of ponzu. The dish is inspired by a friend and regular who owns a sushi joint in the Richmond. You can also order by the half dozen for a smaller version.

Smørrebrød, a.k.a. Open-faced Sandwich

Smørrebrød is an impossible-to-pronounce open-faced sandwich that’s served throughout Denmark for lunch. It’s usually served on dense Danish rye bread and topped with various goodies, ranging from smoked fish to cold cuts to potato salad. At Swan Oyster Depot, you can get basically the same thing — a combination salad topped on three small slices of bread (specify sourdough or rye). They will slather Louie dressing on the bread so it soaks in, then top with lettuce and a mix of fresh seafood. It’s divine.

Fun fact: The founders of Swan Oyster Depot — originally named Cable Oyster Depot — were a pair of Danish immigrant brothers named the Laustens. After the 1906 earthquake, the Laustens relocated to the present-day location. They renamed it, too, because swans are a symbol of prosperity and fertility in Denmark.

Red-eye

This is Swan Oyster Depot's version of hair of the dog. Served only on Saturday mornings, it is a mix of Bud Light with cocktail sauce, lemon juice, Tabasco, Worcestershire, pepper and oyster juice. The combination of sweet, spicy salinity will cure the angriest of hangovers.

Hot Lobster Salad

It’s no secret that you can get a large Maine lobster steamed to order — it’s written on the board. But what’s not listed is that they can break down the sweet lobster meat for you and make a salad out of it. Pro tip: Ask for a side of drawn butter to go with the salad and they’ll mix in the unctuous lobster tomalley in it.

Combination Salad Sandwich

There will never not be a line at Swan Oyster Depot. The best option for those in a rush is to skip the line and make a takeout order. Order a combination salad sandwich — they’ll hollow out a piece of sourdough and stick a combination salad in between. This is the perfect on-the-go option and is probably the most game-changing item on this list.

Uni

The uni also isn’t always available, but also isn’t totally a secret. (When they do have it, they’ll display it near the window in plain sight). When it is available, order it and they’ll serve it to you in its still-moving spiny shell. Pro tip: Ask for a side of soy sauce and they’ve got you covered.

Supreme Cocktail

If you’re hungry, you can get a double seafood cocktail that’s served in a sundae glass. But if you’re really hungry, as one regular often is, you can get a “supreme” cocktail that’s served in a large chowder bowl. It amounts to roughly the size of 3½ normal cocktails. Fewer than a dozen people know about it and order it each year.

Swan Oyster Depot, 1517 Polk St., San Francisco; (415) 673-1101

Omar Mamoon is a freelance writer based in San Francisco and founder of Dough & Co.