Loh bok goh, often called radish (or turnip) cake or pudding, or carrot cake (in Malaysia and Singapore), is available year-round but is especially good in the winter, when the loh bok - white radish (also known as daikon) - is crisp and sweet. It's also associated with the Lunar New Year because it's supposed to bring good fortune. It's delicious freshly made and hot out of the steamer, sliced then pan-fried (which is how dim sum restaurants serve it) and stir-fried with XO sauce.
If you like, add a few conpoy (dried scallops) to the other mix-ins/topping. Soak the scallops with the mushrooms and shrimp, then shred into small pieces when soft.
Put the mushrooms and shrimp in a bowl, add about 300ml (1¼ cups) of cool water, then leave at room temperature until fully hydrated. (This can take several hours, depending on the mushrooms; if you prefer, soak them in the fridge overnight.)
Trim off and discard the top of the radish, then peel it. Grate with a large-toothed grater (it's easiest with a food processor). You should have 1kg (35oz); if you have more or less, multiply the weight (in grams or ounces) of the grated radish by 0.01 to determine the correct amount of salt. Put the grated radish in a bowl, add the salt and mix well. Leave at room temperature for about 30 minutes. Drain the radish through a colander. Take handfuls of the drained radish and squeeze to remove the excess moisture, then put the solids in a bowl.
Drain the hydrated mushrooms and shrimp, but reserve the soaking liquid. Squeeze the mushrooms to remove the excess liquid, then cut off and discard the stems. Cut the caps into 5mm (¼in) cubes. If the shrimp are large, cut them into smaller pieces. Quarter the lap cheong lengthwise, then slice into 5mm (¼in) pieces. Finely dice the char siu.
Heat a wok over a medium-high flame, add about 5ml (1tsp) cooking oil and rub it into the wok with a paper towel. When the wok is hot, add the lap cheong and stir-fry until the pieces start to brown. Add the shrimp, mushrooms and char siu, stir-fry for about a minute, then remove from the wok and set aside to cool.
Strain the mushroom and shrimp soaking liquid into a measuring cup. Add 250ml (1 cup) of the soaking liquid to the bowl containing the drained radish and salt and stir thoroughly. Mix in the rice flour (adjusting the amount as needed, if you had more or less grated radish) and the white pepper. Stir in about two-thirds of the lap cheong, shrimp, mushrooms and char siu, reserving the rest for scattering on the top of the loh bok goh.
Lightly oil a 23cm (9in) round pan that’s at least 5cm (2in) deep. Stir the ingredients thoroughly before scraping into the prepared pan. Scatter with some sesame seeds and the reserved lap cheong, shrimp, mushrooms and char siu. Place over a rack in a tiered steamer (or a wok with a low-footed rack), cover with the lid and steam on high for about an hour and 15 minutes, or until a thin metal skewer inserted into the pudding comes out clean, without sticking. Check the water periodically to make sure the steamer doesn’t run dry.
The pudding can be eaten as soon as it's steamed. If pan-frying or stir-frying the loh bok goh, leave it to cool to room temperature, then refrigerate until firm. For pan-frying, cut into thick slices and place them in an oiled skillet over a medium-high flame. Pan-fry until crusty on all the cut sides. If you like, drizzle the loh bok goh with a little light soy sauce before serving.