Gooey, tangy cheese, melted over carmelized onions, a generous dose of sherry, rich broth and french baguette - this may be my desert island food.
Not a soup to make if you are in a hurry. I started with Cooks Illustrated (a favorite source for recipes because every step and ingredient choice is analyzed).
Step one - carmelize your onions - I did this by putting about 4lbs of sliced onions in the oven at 400 degrees with about 3 - 4 Tbsp of butter and a tsp of salt. The oven works better than the stovetop - you can stir the onions every hour or so (and scrape the bottom and sides of the pot) instead of constantly stirring and adjusting the flame, you will get more flavor out of the onions this way too. By the way, caramelization is the oxidation of sugar, a process used extensively in cooking for the resulting nutty flavor and brown color.
The process took about 2 3/4 hours. The result are rich brown onions in a fabulous, slightly thickened, caramel colored juice.
Once the onions have carmelized, you can cook them on the stove for about 20 min over medium -high/medium (keep and on eye how fast the liquid evaporates) heat. Keep cooking it until you evaporate the liquid, making the onions even yummier and browner, and forming a wonderful dark, brown crust.
Using water, 1/4 cup at a time, deglaze the pan. Pour in the first 1/4 cup - scrape the crust off the bottom and sides. Don't worry - it probably won't all come off the first tiime. It took me 3 goes with the water to get all the crust back into the onions.
Now it is time for the sherry. Just like cooking with wine, if you wouldn't want to drink it, you shouldn't cook with it. I added 1/2 Cup. Cook off the alcohol - about 5 minutes. Next add in about 6-8 cups of liquid. Recipes I have seen use some combination of chicken and beef broth - the more beef, the richer and browner the soup - but if you are using store bought beef stock, I would say go 50 -50 - you can even add water for the last two cups - that way you don't lose the flavor of the onions. For my soup I used 4 C homemade brown chicken stock, 2 Cups store bought beef stock (I ran out of homemade) and 2 C of water.
I add fresh thyme - 6 healthy sprigs - I like the flavor of thyme in this soup, 1 bay leaf and salt to taste. Make sure all the crust is scraped off the sides and bottom of the pan. Bring to a simmer, cover reduce the heat and simmer for about 30 minutes. Toss the herbs add salt and pepper to taste - go slow with the S & P - too much of either can really throw off the balance - keep tasting until it is right.
Now for the fun part. Figure 2 slices of baguette per bowl - toast the baguette slices (or bake at 400 deg for about 10 minutes until crisp).
Fill individual broiler safe bowls with about 12 oz of soup, top with two baguette slices and sprinkle with shredded Gruyere. Cover the bread evenly - at least one ounce of cheese per bowl. Broil for about 5 minutes until the cheese is bubbly add nicely browned. Let the bowls stand for a few minutes and enjoy.
