Nutella cannot be microwaved. If you do so, it hardens! :( Crap, I think I may have just wasted nearly half a jar of Nutella... I couldn't get it to swirl into the muffin mix like I planned so I had to sort of dollop it onto the batter once it was in the tin. We'll see what happens in about 12 minutes.
Did I mention I'm not much of a kitchen person?