This was a HUGE hit. The trick is to let it simmer most of the second day until it's reduced by more than half. Trust me, it makes a rich, beefy soup that's much better than the than the one you'll get if you don't.
My kids are a bit snobbish about their French Onion soup and they approved. I don't have oven safe individual bowls so once I baked the croutons, I added the cheese and broiled and then we put a cheesy crouton in each bowl. I had a little extra because I was using up a loaf of homemade sourdough so a couple people got two cheesy croutons. Will definitely make again.