Step-By-Step Method

1. Yudane:
1. Add bread flour in a bowl, pour the boiling water and mix well with spatula or spoon until no dry flour.
2. Cling film and place in the fridge for at least 4 hours or overnight.  I prepared the night before.
3. Use directly from the fridge.
2. Sweet Stiff Starter 
1. Dilute starter with water, stir in sugar and mix in bread flour to become a dough.  I usually mix with plastic scrapper then mix with hand to make into a ball.  Please use stand mixer with paddle attachment to mix if you find hard to mix with hand.
2. Cover and let it ferment until tripled. I prepared a night before and leave it in aircond room (approximately 24 - 25C room temperature) overnight until tripled.  It took about 8 - 9 hours depending on your starter.  It should take around 4 - 6 hours to get triple at room temperature at 28C - 30C. The starter should look smooth and round dome.  It shouldn't collapse.
3. Main Dough:
1. Put all ingredients (except olive oil and raisins), including all the stiff starter and yudane dough into a bowl of stand mixer.  I usually torn the stiff starter and yudane dough into pieces first.
2. Slightly combine the mixture by hand with the paddle attachment before turning on the machine so that the flour will not splash out.  Using the paddle attachment, mix for 2 minutes or until all incorporated.  This step is critical to prevent  an uneven mixed dough as the stiff starter is rather hard and a dough hook may not be able to mix it well enough.
3. Change to hook attachment and knead for another 3 minutes or until the dough comes together. Add in olive oil in 2 - 3 batches and knead until oil incorporate with the dough.  It took quite a while about 5 - 6 minutes for the oil to blend into the dough. Once the oil is well incorporated with the dough,  then continue kneading for another 7 - 8 minutes (approx.) or until the dough become smooth, silky and reach window pane stage. The whole kneading process, I stopped few times to scrape down the dough from the hook to be sure it is evenly kneaded and also to prevent the motor from overheating.
4. Fold in raisins.  Round up the dough and put back in the same bowl. 
4. 1st Proofing/Resting:  
1. Cover with lid and let the dough rest for 45 - 60 minutes. Keep it covered with clingfilm or use a lid.  This dough I rested for 60 minutes at 29C room temperature and the dough rose about 50%.  It is fine if your dough doesn't rise a lot.
5. Shaping:
1. Transfer the dough to a clean floured surface then divide dough into 12 equal portions (around 78g each).  Please use a kitchen scale if you want to be exact.  
2. Form each portion to a ball.  Please watch the video.
3. Place place bun onto the prepared baking pan (arrange 3 buns X 4 buns).
6. Final Proofing:
1. Let the buns proof at a warm place until the dough rise double in size. This one took approximately almost 2 hours at at room temperature of 30C.  The duration of proofing depends on your ambient temperature and the starter.
7. Flour Paste for The Cross:
   1. Whisk flour, water and oil together until become a thick pipeable paste.  Transfer the paste to a pipping bag and snip the tip off. Set aside.  I used a round nozzle instead.   If you do not have a piping bag just used a clean plastic bag and snip the tip/corner off.  
8. Sugar Glaze:
1. Combine both sugar and boiling water in a small bowl, stir until sugar resolve.  Set aside.
9. Baking:
1. Preheat oven at 190C - 210C (top & bottom heat) or 170C - 190C (fan-forced) for 15 minutes.
2. Pipe a cross on each bun with the prepared paste.  Please watch the video.
3. Bake in a preheated oven for about 20 - 25 minutes, or until golden brown.  Please do not over baked as the buns will become dry easily by the next day even though yudane method is used.  Every oven behaves a little differently, so please adjust accordingly for your oven. The ceramic pan I used is a poor heat conductor and took me around 25 minutes to fully bake the buns.  
4. Remove buns from oven and let them cool on rack.  Brush buns with sugar glaze once out from oven.