French onion soup is absolutely fabulous … just sayin’. The recipe I started with many years ago came from James Peterson’s ‘Splendid Soups’ cookbook, I think it was 2004 or 2005. Back in those days I slaved over a pot of onions for hours trying to get the perfect caramelization and making sure nothing burned. Until one day, one day that changed my soup making life forever. I opened up my new, autographed by Christopher Kimball, America’s Test Kitchen TV Show Cookbook. It’s the first 10 years of the shows recipes compiled into a rather large, GORGEOUS, cookbook. It was in the pages of this that I discovered THE secret to “low and slow” caramelized onions … let the oven do the work for you and get off your feet.
The recipe below is my version based on a hybrid of the two cookbooks listed above, and tried and true testing and tasting.
TIPS:
- Use sweet onions – onions have a lot of sugars already but sweet ones caramelize the best. I use either Maui sweets or Peru sweets. Vidalia onions are particularly sweet and come from the South.
- You can use chicken or beef broth, or a combination of both. When making broth we prefer to use chicken and/or beef base rather than cubes or powder.
- In my opinion, the only alcohol that should touch French onion soup is a good dry sherry such as Cutty Sark in the burlap sack. Sherry has a wonderfully distinct sweetness that adds to the caramel flavor of the onions and plays off the thyme really well. Add a pinch of kosher salt and you have a perfect marriage.
- 4-6 tbls unsalted butter
- 5 lbs of sweet onions cut in half and sliced ¼" thick lengthwise
- Healthy pinch of kosher salt
- 2 cups of beef broth for deglazing
- ½-2/3 cup dry sherry
- 8 cups of beef broth
- 6 sprigs of fresh thyme tied together with kitchen twine, or use 3-4 tsp of dried thyme
- 1 bay leaf
- Salt and ground black pepper to taste
- 1 baguette French bread cut into ½" slices and toasted on a baking sheet for 10 minutes in a 400° oven
- Grated Gruyere cheese
- Adjust an oven rack to the center position and preheat to 400°.
- Liberally spray a large dutch oven with a lid with non-stick cooking spray. Cut butter into large pieces and place in the bottom of the dutch oven.
- Place sliced onions on top of the butter pieces, spray lid to dutch oven with non-stick cooking spray and place on dutch oven to cover. If the lid doesn't fit tightly that's okay, the onions will break down and the lid will drop into place on its own.
- Put pot into oven and cook with lid on for one hour. The onions will start to break down and release their liquid. Remove the pot from the oven and stir onions, making sure to scrape down the sides and bottom. Put pot back into the oven for 1 hour with lid slightly cracked to allow steam to escape and the onions to break down and caramelize. Stir onions and scrape down sides and bottom, put pot back into oven for 1 more hour with the lid slightly cracked.
- Take pot out of the oven and place over medium-high heat on the stove. Continue cooking the onions, stirring frequently scraping the sides and bottom until liquid evaporates and onions continue to brown, roughly 20 minutes or so. Reduce heat if onions are browning too fast.
- Use two cups of beef broth, ½ cup at a time until completely evaporated, to deglaze the pan and dissolve any brown bits that have collected on the sides and bottom of pot. This takes another 20 minutes or so.
- Add dry sherry and cook, stirring frequently, until the sherry evaporates, about 5-7 minutes.
- Stir in 8 cups of beef broth, add thyme, bay leaf, and salt/pepper. Scrape down sides and bottom of pot to remove any final brown bits, increase heat to high and bring to a simmer. Decrease the heat to low, cover, and simmer for 30 minutes. Remove thyme sprigs and bay leaf, discard, then taste to adjust salt and pepper.
- Ladle soup into bowls and place toasted baguette slices on top of soup, top with a healthy amount of grated Gruyere cheese and put bowls on a baking sheet. Place under a broiler for 5 minutes or so until the cheese is bubbly and golden brown.