Quite possibly my singlemost favourite Bangkok street dish is actually four different but nearly identical dishes using seemingly similar, but actually rather disparate ingredients, combined in ways that run a diverse spectrum from gooey to crispy. Let me explain...
Or suan (อ่อสวน) is made by frying a batter made from paeng man (แป้งมัน), tapioca flour, along with egg and oysters. The batter made from this particular type of starch tends to remain soft, sticky and stretchy -- essentially the point of this dish, which takes the form of a sort of gloopy oyster pancake.
A good example of or suan is the version served at Hoy Thot Texas, a 70-year old shophouse restaurant in an alleyway in Bangkok's Chinatown. The proprietor/chef here, an older woman who speaks Thai with an endearing Chinese accent, fries the ingredients on a wide, flat pan, intertwining the thin batter, egg and oysters in a barely-set, oily mass. It's not an attractive dish:
and to be honest, it didn't have heaps of flavour, but it's indicative of the soft, squishy texture that defines old-school or suan.
Hoy Thot Texas/หอยทอดเท็กซัส 77-77/1 Trok Sai (Soi Texas, off Th Phadungdao) 9am-6pm
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Not all vendors go that gloopy though, some opting instead for a slightly more set, almost omelet-like version of the dish. Nay So, another Chinatown old-timer, does a good example of this take (pictured at the top of this post). The or suan here is prepared and served on a sizzling hot plate, and unusually, arrives topped with a pile of beheaded bean sprouts. The hotplate continues to cook the dish even after it's been served, and the result has all the flavours of a good or suan, but none of the gloopiness.
Nay So/นายโซว 3/1 Th Maitri Jit, Bangkok 11am-2pm & 5-9pm
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The crispiest -- and most common -- version of the batter/egg/shellfish combo is hoy thot (หอยทอด), mussels and egg fried with a batter, and served on (or sometimes topped with) a bed of flash-fried bean sprouts and green onion. In English, I usually refer to the dish as 'mussel omelet', but have come to like Andy Ricker's 'crispy broken crepe', which although it doesn't exactly roll off the tongue, is probably more indicative of the way the dish is made.
Hoy thot is made more or less the same way as or suan, but here the batter is fried until crispy. The starch used is generally a mixture of tapioca and rice flours, the latter as it's able to obtain the crispy texture associated with the dish. At Yu Huat, a longstanding stall in Bangkok's Chinatown, they use paeng thao yay mom (แป้งเท้ายายม่อม), a type of flour made from Polynesian arrowroot, an old-school ingredient that few vendors nowadays use. The flour is allegedly combined with stock, not plain water, and the result is a textbook version of the dish: crispy and rich, slightly peppery, and topped with barely-cooked mussels:
Like all the places mentioned here, Yu Huat fries the dish in lard, but not over coals -- at least not any more. "That was during grandpa's time! It's just too much work," I was told upon asking.
Yu Huat/ยู่ฮวด หอยทอด Soi Phiphaksa 2, Bangkok 11am-8pm
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Blurring the lines even further, many of the same vendors who do the dishes above employ the same ingredients used to make or suan -- oysters, egg and tapioca flour -- in a dish call or lua (ออลั่วะ). In this version, the normally soft batter is fried until shatteringly crispy -- similar to hoy thot -- then topped with barely-cooked oysters. A great version of this dish -- crispy, lardy, smokey (because here they do cook over coals) -- can be got at Nay Mong.
Nay Mong/นายหมง 539 Th Phlap Phla Chai 02 623 1890 5-10pm
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Some of the shops that do the dishes above also do one more dish that can more or less be slotted into this category. Although you'll find no shellfish, and the dish is accompanied by soy sauce, not sweet chili sauce, khanom phak kaat (ขนมผักกาด):
fits the familiar pattern of a batter -- in this case a heavy dough made from rice flour and shredded white radish -- fried with egg, sprouts and green onions.