French Onion Soup
Real French onion soup lives or dies by the onions. Rush them and you get watery broth with blonde onion bits. Take the time to caramelize them properly and you build the deep, sweet foundation that makes this soup worth the wait.
Low and slow wins this race
The onions need at least 45 minutes of slow cooking to caramelize properly. Don't rush this step — the difference between good and great French onion soup happens in those final 15 minutes when the onions turn bronze.
- large heavy-bottomed pot
- ladle
- oven-safe bowls
- cheese grater
What goes in.
- 3 lbyellow onions, sliced thin
- 4 tbspbutter
- 1 tbspolive oil
- 1 tspsalt
- 1 tspsugar
- 1/2 cupdry white wine
- 6 cupsbeef stock
- 2 tbspfresh thyme
- 2bay leaves
- 6 slicesday-old baguette, 1-inch thick
- 2 cupsGruyère cheese, grated
- 1/2 cupParmesan cheese, grated
Cook until the onions stick slightly
When properly caramelized, onions will stick lightly to the bottom of the pot and release easily when stirred. This fond builds the deep flavor that makes the soup.
The method.
Start the onions
Heat butter and oil in a large heavy pot over medium heat. Add onions and salt, stirring to coat. Cook uncovered, stirring every 10 minutes.
Caramelize slowly
After 30 minutes, add sugar and reduce heat to medium-low. Continue cooking 15-20 minutes until onions are bronze and jammy. They should stick slightly to the pot bottom but release when stirred.
Deglaze
Pour in wine and scrape up any browned bits. Cook until wine reduces by half, about 3 minutes.
Build the soup
Add beef stock, thyme, and bay leaves. Bring to a boil, then simmer 20 minutes. Remove bay leaves and taste for seasoning.
Prepare for broiling
Heat broiler. Toast baguette slices until golden. Ladle soup into oven-safe bowls, top each with a bread slice, then pile on Gruyère and Parmesan.
Broil and serve
Broil 2-3 minutes until cheese bubbles and browns in spots. Serve immediately while cheese is still molten.
Other turns to take.
Vegetarian Version
Use mushroom or vegetable stock instead of beef. Add a splash of soy sauce for umami depth.
Classic Cognac
Replace wine with 1/4 cup cognac for traditional French bistro flavor.
Mixed Cheese
Combine Gruyère with aged cheddar or Comté for different melting characteristics.
When it doesn't go to plan.
Slice onions pole to pole, not across the equator, so they hold their shape while cooking
If onions start browning too quickly, lower heat and add a splash of water
Day-old bread holds up better under the broiler than fresh
Make the soup base a day ahead — the flavors improve overnight
The ones that keep coming up.
Can I use a different type of onion?
Yellow onions work best for their balance of sweetness and sharpness when caramelized. Sweet onions like Vidalia will work but lack some depth.
What if I don't have oven-safe bowls?
Toast the cheese-topped bread separately under the broiler, then float it on top of the soup in regular bowls.
How do I know when the onions are properly caramelized?
They'll be bronze colored, jammy in texture, and taste sweet with no sharp bite. The process takes at least 45 minutes — don't rush it.