This is one of the the things that I will order when dining in a dimsum restaurant. I love how the slight sweetness of the yam complements well with the savoury and juicy filling. This is the second time I did it, two days ago, I made it with the first batch of frying was successful. I got the perfect honeycomb exterior that is crispy and flaky. However, I failed to achieve the perfect honeycomb on my second batch of frying. I have a hunch of what went wrong, so today I tested my hypothesis.

The yam dough has to have the right proportion of wheat starch and shortening or you will end up a doughy texture. It is also important to maintain the right oil temperature, which is about 160-170 degree celsius. You can test it by dipping in a wooden chopstick. Bubbles surrounding the chopstick means that it is of the right temperature that we need. However if the bubbles are moving rapidly, it means the oil is already too hot. You have to control the temperature on your second batch frying, in my case I turned down my fire to the lowest, and waited about a minute before I put in my second piece, because the temperature reading I got was about 190 + degree celsius. Waiting for a minute won’t bring down the temperature to 160 yet, so I found a work around by quickly dunking the yum puff in and out of the oil using a frying ladle(skimmer strainer) until you see honeycomb forming before letting it stay in the oil to fry until golden brown. Alternatively, you can turn off the heat completely and wait until the oil comes down to the right temperature; if you have time and like to have beautiful honeycomb for every piece. The work around is good with slight compensation on its honeycomb texture, refer to attached photos below to show the comparison. Do remember to place the puff on the frying ladle all throughout the process and remove any floating particles after each batch of frying.

Ingredients (yam dough)

• 210g yam (steamed and mashed)
• 84g wheat starch
• 80g shortening or lard ( I used shortening)
• 50g hot water
• 2 tsp sugar
• 1/8 tsp salt
• 1 tsp five spice
• 1 tsp sesame oil

Filling

• 30g carrots (diced)
• 65g prawn (chopped into a small pieces)
• 125g minced pork
• 30g shiitake (diced, I used fresh)
• 3g minced garlic
• 5g minced shallots
• 1 stalk of green onions (chopped)

Gravy

• 1/2 tbs oyster sauce
• 1/2 tbs light soy sauce
• 1 tsp sugar
• 62g water
• 1 tsp potato starch

Method (Filling)

• Combine all the gravy ingredients, mix well and set aside
• In a heated wok at medium high fire, drizzle 2 tbs oil
• Add in the minced shallots and garlic, stir fry until fragrant
• Add in the minced meat, stir-fry until it becomes brown. Break up the meat into bits.
• Add in the carrots and shiitake, stir-fry until the mushrooms are wilted. Add in the prawn. Stir-fry until the prawns are 80 percent cooked, then add in the gravy. Stir well and let it come to boil.
• Turn off the heat, add in the chopped spring onion. stir well to combine. Set aside and let it completely cool down. You can prepare the filling one day ahead. For me, I find that cold filling is easier to use.

Method (Yam Dough)

• Prepare a tray, lightly flour it with wheat starch and set aside.
• Add the water into the wheat starch, mix until all comes together and formed a dough. like shown on the picture. The dough is a bit dry, it is fine.
• Add in the dough into the mashed yam. Add in the sesame oil, sugar, 5 spice and salt. Mix until well combined, see photo below
• Add in the shortening and mix well to combine. I used a hand with glove to mix everything together. It is essential that you mix well all ingredients, so you should not be seeing any clumps of shortening on your yam dough. The final result would be a sticky paste.
• On your working mat, sprinkle some wheat starch, put the sticky paste on top the floured area and slightly knead your yam into a dough that is easier to handle. I put about 2-3 tbs of wheat starch to work on. See photo below
• Get about 35g of dough and flatten it into a round disk. Fill it up with 1 teaspoonful of filling. Wrap it like the shape in the photo shown below. Place the uncooked yam puff on the tray. Do the same for the rest of the dough
• Heat up the oil on your frying pan at medium heat. The pan has to be filled enough with oil to deep fry your yam puffs. Allow the oil to heat up and reach about 160 degree celsius.
• Dip in the frying ladle into the oil. This is to prevent your yam puffs sticking on the ladle. Place the yam puff on the ladle with enough spacing in between. If your ladle is big, you can put several pieces together. I have tried working on big and small ladle, with single puffs or multiple puffs. Both works fine a long as you have enough spacing and the proper oil temperature. Dunk in and out after a few seconds, you can see the honeycomb forming, then continue to let it fry in the oil until golden brown. Drain it on a paper towel and transfer it to muffin paper. Do the same for the rest of puffs – as the oil temperature further increases, you may continue cooking by dunking the yam puff in and out of the oil faster or turn off the fire to reduce the temperature before continue cooking your next batch.
• Serve hot.

Note : I am using canola. I have tried using rice bran oil using the same recipe, however the result turned out not flaky. I did twice and both had the same result. Third time I did with canola oil and it worked. I am not sure what is the science behind it coz I am quite puzzled. Let me know if you found out the reason.