Rinse dried mushrooms and soak in 180 ml water till soft, about 30 minutes. Squeeze dry, reserving soaking water. Trim stems (may be reserved for making stock another day.) Dice.
30 g Chinese dried mushrooms
Rinse dried prawns and soak in 60 ml water till soft, about 15 minutes. Squeeze dry, reserving soaking water. Chop roughly.
40 g dried prawns
Peel yam. Trim all white parts under peel that don't have much red veins to yield about 300 g. Rinse. Cut corn kernel-sized.
550 g yam aka taro
Peel and rinse shallots. Slice thinly.
100 g shallots
In a wok, stir-fry shallots in hot corn oil over medium heat till lightly golden. Turn off heat. Continue stirring till nicely golden brown. Remove shallots with a skimmer and set aside. You should have about ⅓ cup (80 ml).
80 ml corn oil
Reheat wok and oil till warm. Over medium heat, fry yam till soft (but not brown), 2-3 minutes. Turn off heat. Remove yam to a big bowl. Immediately sprinkle with ½ tsp salt and ¼ tsp five-spice powder. Toss till evenly mixed. Set aside.
½ tsp salt, ¼ tsp five-spice powder
Remove all but 2 tbsp oil from the wok. Reheat till very hot. Over medium-high heat, stir-fry dried prawns till lightly golden. Add mushrooms and stir-fry till fragrant and lightly golden. Add light soya sauce and ground white pepper. Stir till evenly mixed. Turn off heat.
1½ tbsp light soya sauce, ½ tsp ground white pepper
Add stir-fried mixture to yam along with all of fried shallots except 2 tbsp. Stir till evenly mixed. Set aside.
Line bottom of 20 x 20 x 5 cm cake pan with parchment paper, leaving some overhang.
Top up dried prawns and dried mushrooms soaking liquid with water to make 240 ml. Pour liquid into wok and stir to deglaze. Add rice flour. Stir till smooth. Add boiling chicken or pork stock. Stir till evenly mixed.
200 g rice flour, 600 ml pork or chicken stock, boiling, 240 ml liquid
Turn on low heat. Stir continuously, scraping sides and bottom of wok. Reduce heat to very low as batter gets hot. If lumps appear, turn off heat immediately, stir vigorously till smooth, then turn on heat again.
When batter starts to thicken, add fried ingredients (except the 2 tbsp shallots set aside). Stir till batter is thick enough to coat a spoon/spatula thinly. Go for a thinner consistency if you like your orh kueh softer, and vice versa. Turn off heat.
Transfer batter into pan. Smooth and level batter. Steam over rapidly boiling water till inserted skewer comes out clean or almost clean, about 40 minutes depending on consistency of batter before steaming.
Remove kueh to wire rack to cool down, an hour or so. Unmould by running skewer around edge of pan, then lifting kueh onto a plate. Discard parchment paper. Garnish with spring onions, coriander, red chilli or sesame seeds, and remaining shallots.
2 tbsp spring onions, 2 tbsp coriander, ½ red chilli julienned