French onion miso soup

Do they actually eat French onion soup in France? Or is it like the Guatemalan yogurt: eaten only in Canada. 

not as dark as I would have liked

The basic idea of French onion soup -- according to me -- is to get a sweet broth by cooking the onions until the sugars caramelize. Then you put some rustic bread on top, add gruyère on that, and broil it until the cheese burns a little bit. Unfortunately, my apartment's oven doesn't have a burner at the top, so the cheese shown here didn't get cooked as dark as I would have liked.

Of course, most French onion soup you'll find in restaurants uses beef for the broth. I didn't have any dead cows or bones lying around, though, so I made a vegetarian version. To make up for the lost umami (whatever that is), I added red miso paste. I also added some crimini mushrooms.

Steps

1. Chop four onions into thin slices. The shape doesn't really matter.
2. Stir-fry the onions for a little while in a pot, then add the mushrooms (also chopped) and a pinch or two of herbes de Provence, stir, and cover.
3. Cook covered for a while on medium-low heat, stirring occasionally, until the onions start to turn brown. Once they're brown -- but not burnt -- add water until they are a little more than covered. Simmer for an hour or so.
4. Add white wine vinegar and salt to taste, but go light on the salt since you're going to add miso.
4.5 I forgot to do this, but I think a few ounces of red wine would be good too.

5. Turn off the heat. Put a little broth in a bowl and mix in a tablespoon of miso (more or less depending on the size of the bowl), and then fill to the top with soup.
6. Put a few slices of bread on the bowl, and some grated or sliced gruyère. Broil until the cheese starts to bubble and turn brown on the edges. Be careful taking the bowl out of the oven.