Panettone / Pandoro / Brioche 

Hi hope everyone is doing well. I wanted to experiment with making a Panettone this year and was wondering about the crumb of a Panettone/ Pandoro and why the two doughs? So far from what I have found the crumb ranges in appearance, but an open soft, tearable crumb seems to be everyone aims for. 

Initially thought that the Panettone / Pandoro would be highly enriched, more that that of brioche and you would need to do the two doughs to prevent any sourness creeping in and strength to push the dough to that level of proof. According to some of the recipes I looked at the butter / yolk ratio is between 40 – 60% of total flour including the LM, with total hydration(eggs, butter, liquid) to be upper 60's to low 70's. Pretty sure there will be exceptions to to rule but I normally break down recipes this way and build around by own starter and flour.

The brioche I use to make was between 40% and 60% butter/whole egg and total hydration around the 50%, depending on what I was using it for. When I used it for cinnamon buns, would hand mix a sweet starter(60% hydration, 50% Mother) in the afternoon and use it the next day usually around 18h. Mix everything, 2h bulk, fridge for around 4h and roll out, proof on the counter for around 8h. Never bothered with checking temperature or pH, no sourness and never failed me. 

The crumb of this dough if used for the cinnamon buns, was soft, open and tearable, probably slightly over-proofed (image attached, sorry about the filters cant find the original) but worked for my schedule. When baked in a tin, I would get a soft fluffy crumb you would find in Shokupan. When I initially looked at developing this brioche dough, when hitting hydration levels of 60's, normally by increasing butter / eggs the crumb open up as expected, the hydration I decided on was for easy of rolling and ferment time. 

At this point, a simple explanation, to me it seems that Pandoro / Panettone looks like a brioche that has a higher hydration to allow to crumb to open up. Rambling but would it not be possible to do a single dough Pandoro / Panettone, or is the multiple doughs more for taste and keeping quality rather that just having the strength to proof the dough, without the sourness, or maybe just tradition at this point. 

Could the sweet starter I used for brioche be considered and first dough, as it was made from stiff starter, although only fed twice a day, so not really an LM.

All theoretical at the moment, hope to do some baking soon and run some tests. 

Any book / article recommendations on the more technical aspects and reasoning behind the Panettone, “Sourdough Panettone and Viennoiserie“ is on the list so far.