Chocolate ... butter?

Yes,  seemingly M made chocolate butter tonight.  He was trying to make chocolate mousse, but evidently he missed stopping at the "soft peak" stage of whipping the cream and headed into the butter stage.  

You might wonder why I wasn't watching more carefully (after all, it's not like M whips cream frequently (or ever before)) - well, perhaps because M chose to start the mousse right before I started dinner.  So I was rather preoccupied with fixing dinner - and then eating dinner.  

So, no mousse for dessert tonight.  Instead I have a bowl of chocolate butter in the fridge, trying to figure out what best to do with it.  It consists of 10 oz whipping cream and 3.5 oz dark chocolate, now as a mass of grainy butter and some liquid.

So far I've thought of trying to turn it into a buttercream frosting  (not sure how the texture would do).  Or trying for some sort of muffin or quickbread that calls for butter and chocolate/cocoa powder.  Any thoughts?