I accidentally made ganache using unsweetened chocolate, not semi-sweet. Is there any way to sweeten this up and keep the consistency or should I start over?

oh no! I don't know if adding any type of sugar would work!? ...here is a bump for you! I might have to go and look that one up! so sorry that happened to you!

Yes you can add sugar but carefully so that it doesn't crystallize. Perhaps make a really thick simple syrup and add that? Realize tho that the water will change the consistency of the ganache a bit so you may have to add more chocolate.

Thank you both for your responses. Since it's so late tonight I just went ahead and made more, but kept the unsweetened (don't want to waste that much chocolate & cream). I'll try to experiment over the weekend. I agree some kind of simple syrup might work best, but I'm not quite sure how to keep the consistency. We'll see.

I would just keep the unsweetened ganache and use to add to buttercream next time you want to make chocolate bc - the sugar in the bc will balance it out.

You can divide the ganache up into packages that are enough to add to 1 batch of bc and freeze - it freezes well Just be sure to melt it again before you add it to bc.

I use unsweetened ganache in Toba Garretts Chocolate Buttercream, I think its very delicious this way as there is already so much sugar in the recipe. Just be sure to cream the ganache seperatly before adding it to the recipe so that you dont get lumps.

http://www.epicurious.com/recipes/food/views/109248

You could also try corn syrup. I add corn syrup to my ganache all the time, it give it a nice sheen. You cold also use glucose, it's lower in water content.

You can add powdered sugar. I have a recipe that's sort of ganache-y that has chocolate chips, butter, cream, and ps. It starts out like regular ganache but then you beat in the ps. I don't know if it's too late but if not, you can try it.