brown, stirring frequently. As soon as you see a little color, 5 to
10 minutes, lower the heat to medium low and continue to cook,
stirring and scraping the bottom of the pan, until the onions are a
very dark shade of brown, 30 to 45 minutes*.
Add all the stock and another sprinkling of salt. Bring to a
simmer on medium heat, then turn the heat down to low and allow
the soup to cook for another 30 minutes.
Taste the soup and adjust it with salt, Tabasco, and the
balsamic. This is your chance to make the soup taste as great as
possible.
Preheat the oven to 500°F and place 4 ovenproof soup bowls
on a cookie sheet. Add a piece of toasted bread to each bowl and
then ladle the soup over the bread, filling each bowl three quarters
of the way. Top each bowl with some of the grated cheese and
pop into the oven.
Bake until the cheese is melted and starting to brown. Serve the
soup piping hot.
* Besides using a rich, flavorful, homemade meat stock, this is the
other key step in making a world-class French onion soup. You
have to let the onions get dark, but it has to happen gradually.