What to buy: Phan uses salted mackerel, which can be found at many Asian (particularly Chinese) markets either in the frozen section or packed in oil on the shelf. If you cannot find salted mackerel, Phan suggests using any salted fish, called haam yee or hom yu at Chinese grocers. Salted anchovies or sardines, available at most grocery stores, also make good substitutes for salted mackerel.
Special equipment: If you don’t have a large wok and/or a large bamboo steamer, create your own steamer: Take two 24-inch-long pieces of aluminum foil and loosely roll and crumple each one widthwise into a 1-inch-thick piece. Form each piece into an S shape and place both in a large frying pan or a large straight-sided pan with a tightfitting lid. Add an inch of water and bring it to a simmer. Proceed with the recipe, placing the heatproof dish on top of the foil coils rather than in a bamboo steamer.
1Fill a large wok with 1 inch of water and place a large bamboo steamer inside. (The water should not touch the bottom of the steamer.) If you don’t have a wok and a bamboo steamer, use a large frying pan and foil as described above in “Special equipment.” Bring the water to a simmer over medium heat.
2Meanwhile, if using country spareribs, chop the meat with a knife or cleaver until very fine and pastelike.
3Place pork (chopped or ground) in a medium bowl. Add mushrooms, shallot, fish sauce, cornstarch, oil, and a large pinch each of salt and pepper and stir to combine. Check mixture for proper seasoning by forming a small, thin patty. Pan-fry it until the center is no longer pink. Taste, adding additional fish sauce, salt, or pepper as needed, keeping in mind that there will be additional salt in the dish from the salted fish.
4Place pork mixture in a slightly rimmed (to contain the juices) heatproof dish about 8 inches in diameter. Press the pork across the dish to form a large 1/4-inch-thick patty. If using salted mackerel, place it in the center of the pork patty. If using anchovies, scatter them in a single layer on top of the pork patty. Evenly sprinkle with ginger and drizzle with a little olive oil. Carefully place the dish in the bamboo steamer or on top of the foil coils. Cover the wok or frying pan with a tightfitting lid or a sheet of aluminum foil and steam until the mixture is just cooked through, about 8 to 10 minutes. Serve with rice.