>But, that's exactly what I told the OP: Filling the (10" diameter by
>1.25x as deep) pan with 2x the batter, will fill it to the same
>fractional depth as if it were split between the two smaller pans.

Well only a baking test can confirm that.....If the cake batter was
properly made from a balanced recipes resulting in lower batter
specific gravity the edges will reach the pan rim, however if the
batter appears thinner she will unlikely able to get the desired cake
volume...


There are factors in the scaling up of a batch weight in order to fit
the desired pan sizes and quantities that you cannot predict exactly.
that the outcome will be the same. as with the smaller batch.

That is the reason that when changing pan sizes ( to pans that was
never used before) the only confirmation accepted by experienced cake
bakers is the actual test bake. with a formulation in a particular
pan...They will have to use three scaling weights; the computed, and
the plus and minus of the computed batter weight.( or excess or less
of the computed scaling weight.)

Although you can extrapolate from a similar cake recipe and predict
with certainty that the results should be positive but in the actual
situation the outcome is not accurate as there are factors in the
processing a bigger batch that can also influence the result..
For example the baking powder used for recipe designed for a small
pans is not the same as with bigger pans or the cake will have sunken
appearance and coarse crumb structure..

There are other factors that can follow suit in affecting the cake
baking performance but of minor importance to a home baker such as
different oven temperature damper settings, mixing modifications, and
even desired batter temperatures .