Assemble Cryovac bags measuring 10cm/4in by 15cm/6in. Grease the interior with a light film of extra-virgin olive oil. Use about 2g/.07oz per bag for a total of 140g/4.94oz. Be careful to not get any grease close to the top of the bag (inside and outside); otherwise it won’t seal. You will also need a heat sealer.
The desired dough temperature (or DDT) is 24°C/75°F. This is the final temperature you want the dough to be at when it is done mixing.
Combine the flour, poolish, water, and yeast in the bowl of an electric mixer fitted with the dough hook. Mix for 3 minutes on speed 1.
Cover the dough with a plastic bag and let it rest for 15 minutes. Add the salt and mix for 5 minutes on speed 1. If you are making larger amounts of dough, the dough will require more mixing time during the second mixing. The dough should be mixed just enough to reach full gluten development—check the gluten “window”.
Transfer the dough to a floured wooden table and let it bulk ferment for 45 minutes covered with a plastic bag.
Punch the dough down, and fold it onto itself. Keep it covered.
Bulk ferment the dough for another 45 minutes.
Divide the dough into 50g/1.76oz pieces.
To pre-shape the dough, push it down with the heel of your hand and brush off the excess flour from the dough. Roll the dough in toward you vertically, pushing the dough down with your fingertips as you roll it up to tighten the roll and to help de-gas it. Make sure that there isn’t too much flour on the dough; brush it off if you can see it. Roll each piece out into a round ball.
Bench rest the dough for 15 minutes.
Reshape the buns and place each one inside a bag with a slice of truffle. Heat-seal the bag closed.
Proof for 1 to 1½ hours at room temperature, or in a proof box for 45 to 60 minutes at 30°C/86°F with 80 percent humidity.
Meanwhile, turn on a steamer to 100°C/212°F.
Once the buns are proofed, make a small incision on the top right corner of each bag using a pair of small, sharp scissors. This will help the bun expand inside the bag, and it will also be the section of the bag where it can be torn open by the customer to eat.
Steam for 10 minutes until the dough expands to fill the bag completely. Cool to room temperature. Reserve refrigerated and well covered.
To pick up, place the dough in a steamer for 2 minutes before serving.