OK, so, I have this Hazelnut and Almond Dacquoise recipe from the LA
Times that I'm going to make Saturday. Looks pretty straightforward.
The buttercream that fills it, however, calls for 3 TB of instant
espresso coffee powder. (So technically this should be called a H&A
Mocha Dacquoise).

Here's my question. Some of my guests would undoubtedly prefer
chocolate to the coffe flavor. I have looked at various recipes on
the net, epicurious, cooks.com, Bon Appetit, the cooks thesaurus, and
not found what I would call a good enough match to make a direct
substitution of the filler. (In fact, some don't list "dacquoise" at
all, but it's really the filling anyway.) I see that they are
sometimes filled with mousse, or various whipped cream mixtures, or
something that must be frozen. But I haven't found a chocolate butter
cream that I think would substitute exactly. I wonder if changing the
coffee powder to just some good quality unsweetended cocoa would work?
I don't know that using actual chocolate that must be melted would
work, as that is not a dry powder and might change the final texture
or results. Any suggestions? Here's the recipe for the filling, but
I'm not going to type in the meringue plus directions. The three
layers of meringue incorporate chopped hazelnuts and almonds, plus
some vanilla extract and almond extract. Then they just make three
roughly 1/2" thick round meringues that gets filled with the chocolate
butter cream:

3/4 C milk
1/2 C sugar
4 egg yolks
3 sticks unsalted butter (really! - not for the coronary
artery-impaired!)
3 TB instant espresso coffee powder dissolved in 1 TB warm water

shortened directions:

simmer milk and sugar
whisk yolks
combine above two (properly), cook until thick
beat w/ electric mixer whisk until cool
beat in butter
beat in espresso/water mixture
whip until smooth and fluffy

assemble

So, you experts (Kay Hartman? Sheldon?), do you think I could just
substitute cocoa? Another factor is that I hate to keep all my
middle-aged guests (including me) awake w/ that much coffee as a
dessert. I might try to find decaf espresso (is there such a thing?
sounds like an oxymoron), but it sounds like this would also be yummy
w/ chocolate instead, or mostly chocolate and a little coffee flavor,
like 2 TB cocoa and 1 TB coffee.

Hopefully,
betsy