Don't let the bad photo ruin it, though, the recipe is excellent.
2 tablespoons butter
8 onions, thinly sliced
50 ml red wine
50 ml balsamic vinegar
2 liters beef stock
1 bouquet garni
salt and pepper to taste
2 baguette croutons per bowl
Gruyere or Provolone cheese
In a large dutch oven or other suitable pot, heat butter until it just begins to brown. Add onions and cook over medium heat, until they caramelize and brown a bit. This will take some time, don't leave it. Stir occasionally until it happens.
Raise the heat to medium-high and add the wine and vinegar, then the stock. Add the bouquet garni and bring to a boil.
Reduce heat to low, season with salt and pepper, cover and simmer for 45 minutes. Remove the bouquet garni. Ladle into bowls, add the bread pieces, and pile on some cheese. Broil in a hot oven or just torch the cheese by hand like a crazed welder, which is way more fun.