I'm making a VAT of mocha Swiss meringue buttercream. Couldn't find an exact recipe, so I cobbled together a few and added too much unsweetened chocolate. Not horrible, just not sweet enough, has a bit of a bitter aftertaste. Can't just add granulated sugar--it would be grainy, if it even held up. Anyone have any suggestions? I can't bear to throw out that much egg and sugar!!

Ooh, that's a toughy. I always use 70-72% bittersweet. Perfect texture/chocolate flavor.

2 suggestions, you could try making a single extra batch using milk chocolate or a chocolate with as high of a sugar content you can find, the finished SMBC will be really soft and super sweet, then try folding in your bitter batch to see if that mellows it out. OR, make a batch of white chocolate (30% butterfat, not candy melts) SMBC and fold that in, I find that icing so sweet I can't eat it.

Hope that works for you!

Jen