<<Disclaimer: Verify this information before applying it to your situation.>>

I'm just a lurker here, trying to learn more.  However, as a special-needs
dieter, I feel that major events like one's own wedding are exciting and
stressful enough that it's not a good idea to add dietary stress to the
package.  This is particularly true if your fiance uses lowcarbing to
control his diabetes--most of us feel like !@# the day after eating
carbs--not a great way to start the honeymoon.

It is possible to make a number of things that meet the needs of both
diets--at least as long as you don't insist on low fat too.  Instead of
substituting another grain for wheat flour--which probably won't be all
that good anyway--go all the way and substitute a completely different
foodstuff

How about cheesecake?  Either for everyone or as a small upper layer.  They
tend to have less sugar as well as enough fat to slow the absorption of
carbs--and if your honey is lowcarbing, there are some excellent ones that
can be made with artificial sweetener.  Crusts can be made from nuts.

Or even less traditional--a pavlova.  That's the new Zealand version of a
strawberry shortcake made with a meringue instead of cake--lots of whipped
cream--and more exotic fruits or just good old lowcarb strawberries.  You
can use a low-sugar meringue or use artifical sweetener and ground almonds
for body.

I don't bake much but I have made a fairly good sugarless starchless sponge
cake using ground almonds and soy powder (the stuff used to make
soymilk)--so I know it is doable--but only once, so my recipe isn't proven.
 (Most of the time I make "cakes" that are basically meringues with
additions like ground nuts and/or coconut but these are probably too
coarse-looking to fill the bill.)  A professional baker ought to be able to
do better.

Here'a another tip that I usually don't share.  Wise CHOice happens to make
the most delicious sugarless icing.  It tastes just like traditional
European buttercream--but it takes only seconds to make.  However, it has
so much fiber (approximately 16 grams per cup) that it should not be used
by the unsuspecting.  If you use it for your special layer--and most of it
ends up on your faces--the licking will be safe for both of you.  Or just
use artifically-sweetened whipped cream.

Barbara
 Wise CHOice for lowcarb, dairy-free frozen desserts
                   http://ExpertFoods.com