So I should not try 1.5x the recipe in the 3” pan?
I haven’t tried baking anything in a 3” deep pan, so I can’t tell you exactly what will happen, but here’s my thought: the recipe needs additional structure to be baked in a deeper pan, and this compromises texture. Rose maintains that home bakers are generally capable of turning out better cakes than a bakery and I think issues like this are one of the reasons- i.e., a professional bakery would make the cost-effective choice and bake the deeper layer rather than splitting it up into two layers.
Can I even try a 2” layer in a 3” pan?
Forum member Bill has baked a 1.5” layer in a 2” pan and it has worked out, but that was for a 9x2 round, so I’m not sure if it will work with the larger sheet pan.
Why is the Rose factor 7-8? What determines if I use 7 or 8?
This is just personal preference, I think either will work. The 8 will give a higher layer.
I tried a 6” chocolate genoise… The tops look and feel great, but oddly, the bottoms of both are very dark, almost a caramelized crust.
If it’s purely a color thing and it’s just on the crust, I would say there was too much heat on the bottom of the pan. Your pan may have been dark or the oven, hot. But if there was a thicker, dense layer at the bottom, then the genoise could have been underbeaten or over-folded. Or, if you made the chocolate bar genoise (as opposed to the cocoa powder gen), a higher % chocolate than called for will also cause a dense layer at the bottom.