Hi,
As suggested, I am making apricot filling for my almond-flavored golden dream wedding cake (to be iced with white chocolate mousseline buttercream). 
I am experimenting with apricot puree, using agar agar to gel/stabilize it.  It’s a bit dense so far—very lightly sweetened tcb apricot puree.  Will it be stiff enough as is?  Too heavy?  I was thinking of folding in something that will freeze well, then hold well in the heat—not whipped cream, maybe some butter cream?  Very grateful for all I’ve learned from reading forum entries this week—wow, you all have done some baking!  Thanks for your help!

When I make the lekvar (with California apricots) it is a very thick paste.  Is that how yours turned out?  I was thinking it would probably be fine on its own, but if you’re worried and want to add something you could use a little gelatin.  I think agar would be too firm when you’re starting with a firm paste. 

If you want to go the buttercream route, you’ll have to be careful not to add too much lekvar/puree to the buttercream or it will break the emulsion.  In other words, I’m not sure it would work to fold just a little buttercream into the puree.  Definitely try it first with a small amount to see what happens.

The apricot lekvar/puree is lovely with the silk meringue buttercream and with mousseline (I also add vanilla for the mousseline).

Katey Lou, Have you considered simple apricot jam, strained and slightly reduced. Julia used that a lot for glazing and I have filled italian weeding cake with it with success.

Thank you both.
I did indeed cook up a test batch of rubbery agar-agar-thickened apricot puree.  So I cut it 1:5 with unthickened puree and threw in a little Amaretto for good measure.  It now has a nice texture—punchier than a jam would be and I can build it up to a quarter inch.  It tasted very good in the last test cake (served yesterday in honor of my mom’s b’day) which was golden almond cake filled with the apricot, iced and decorated with white chox mousseline buttercream (also w’ amaretto).  I think it’ll do!  And the whole construction seems very stable while staying moist enough. Yay!

On to production, decoration, storage, transportation and serving.

Katey Lou, Remember what Rose taught us in TCB- there are only 2 peoples to be trsuted with transporting a wedding cake- the person who made it or the person who paid for it. If you didn’t get paid, I guess you know who that leaves to transport it…. I’ll wish you ‘break a whisk’ rather than ‘break a leg’. Take some photos and post as you progress.