I LOVE French Onion Soup. I hadn't made it yet this season, so I made a big pot this weekend. I froze half of it, and served the rest for a Sunday lunch. The kids don't mind it, but they tend to supplement a much smaller portion with a grilled cheese or salad.
The key to the amazing flavor is the caramelizing of the onions, so take your time and do it right. You can do it a day or two in advance if you like, as long as you're cool with onion-ing up your house for 2 days (my kids are always horrified with the oniony aroma when they come home on a day I've been reducing a big pot of onions). I also recommend making the soup a day or two before you're going to serve it - the flavor is even better when you give it a little time. The recipe below looks long and involved, but it's really not bad at all. You can walk away from the onions while they're in the oven, as long as you set a timer, and the stove time is not bad. Give it a try!
Fabulous French Onion Soup
Adapted from From Cook's Illustrated
2-3 tbsp. unsalted butter
4-6 large yellow onions, sliced thinly (I use my mandoline)
2 c. water, plus extra for deglazing
1/3 c. dry sherry (Don't buy cooking sherry, please - it's salty and gross. Go to the wine section.)
4 c. low-sodium chicken broth (Swanson Natural Goodness is good)
2 c. beef broth (Swanson Natural Goodness is good)
6 sprigs fresh thyme (tie with twine if you have it - makes it easier to retrieve stems)
2 bay leaves
salt & pepper to taste
(I prefer these to the giant glob of melted cheese on top that you often get at restaurants.)
1 small baguette, cut into 1/2-inch slices
approx. 2 c. shredded Gruyère cheese (I've used a combo of Swiss and Asiago, too)
Adjust oven rack to lower-middle position and heat oven to 400 degrees. Spray inside of heavy-bottomed large (at least 7-quart) Dutch oven with nonstick cooking spray. Place butter in pot and add onions and 1 tsp. salt. Cook, covered, 1 hour. We're not done.
NOTE: Do not forget to wear your oven mitt when you remove and replace the cover of your Dutch oven over and over during the process. Not that I have ever done that.
Remove pot and stir onions, scraping bottom and sides of pot - you'll see some liquid in the bottom of the pan, and your heap o' onions will have reduced a bit. Return pot to oven with lid slightly ajar and continue to cook for another hour, and stir again. Continue for another 30-45 more minutes, until onions are golden brown and soft. I have stopped at this point, and refrigerated my onions for a day or two.
Place Dutch oven on the stove over medium-high heat. Don't walk away during this step - you need to watch so you don't end up burning that golden goodness! Cook onions, stirring frequently and scraping bottom and sides of pot, until liquid evaporates and onions brown, 15 to 20 minutes, reducing heat to medium if needed. Continue to cook, stirring frequently, until pot bottom is coated with dark crust, 6 to 8 minutes, adjusting heat as necessary. (Scrape any fond (the dark, gooey good stuff) that collects on spoon back into onions.) Stir in 1/4 cup water, scraping pot bottom to loosen crust, and cook until water evaporates and pot bottom has formed another dark crust, 6 to 8 minutes. Repeat process of deglazing up to 3 more times, until onions are dark brown. Scrape down the sides and bottom of the pot for any remaining bits of fond. Stir in sherry and cook, stirring frequently, until sherry evaporates, about 5 minutes.
Add broths, 2 cups water, thyme, bay leaf, and 1/2 teaspoon salt. Increase heat to high and bring to simmer, uncovered. Reduce heat to low, cover, and simmer 30 minutes. While the soup simmers, make your cheese croutons. Arrange baguette slices in single layer on baking sheet, sprinkle liberally with shredded Gruyere, and put under the broiler until cheese begins to bubble. Set aside until it's time to serve. Remove and discard the bay leaf and thyme stems and season with salt and pepper. Ladle into bowls, add a cheese crouton or two, and you're ready to go. Enjoy!