Best Spices for French Onion Soup

The real seasoning in French onion soup is time. One tested recipe cooks the onions for more than 2½ hours before the stock goes in, and that long, slow browning does most of the work. The spice list stays short: thyme, a bay leaf, black pepper and some wine, in all three recipes cited here, plus a little nutmeg in one. The cooks don’t agree on the wine or the stock, though.

At a glance

Seasoning	Job in the pot	In the recipes cited
Thyme	Savory, sharp herbal note against the sweet onions	All three¹²³
Bay leaf	Subtle herbal background	All three¹²³
Black pepper	Gentle pungency	All three¹²³
Parsley	Green note, often with thyme and bay as a bundle	Saveur¹
Nutmeg	A faint warm note	Bernard Laurance³
Wine or sherry	Acidity, depth	All three, in different forms¹²³
Gruyère	Nutty, savory topping	All three¹²³

The onions do most of the work

Every recipe here starts with a long, slow cook of the onions. Saveur’s version, based on Patricia Wells’s Bistro Cooking, cooks thinly sliced yellow onions in butter for 40 to 45 minutes until they just start to brown, then about an hour more until caramelized.¹ The America’s Test Kitchen recipe published by PBS SoCal cooks yellow onions covered for an hour, then 1½ to 1¾ hours longer until very soft and golden brown.² Bernard Laurance gives no time and says only that the onions should color without burning.³ Two of the three add a little sugar to the onions.

Forty minutes is the short end of these recipes. The ATK method runs past 2½ hours.

The seasonings and what each does

Thyme: the savory counterweight

Thyme shows up in all three recipes, as whole sprigs in Saveur’s and ATK’s (tied with twine in ATK’s). It isn’t the only herb in every version: Saveur adds parsley sprigs, and all three add bay. Thyme’s sharp, savory edge cuts the onions’ sweetness. America’s Test Kitchen counts thyme as a hearty herb whose volatile flavor compounds hold up somewhat better to heat, so it can go in early and simmer.⁴ Fresh sprigs are easy to fish out. For dried, see fresh thyme vs. dried.

Bay leaf: background depth

Each recipe uses bay, fresh in Saveur’s, and Laurance offers a bouquet garni as an alternative to thyme and bay.³ The classic bouquet garni is sprigs of parsley and thyme and a bay leaf, removed before the dish is served, and Saveur’s herb list matches it exactly. Bay tastes herbal, bitter and slightly piney, and J. Kenji López-Alt says it brings out the meaty flavors of beef and chicken. Take the leaf out before serving; López-Alt compares eating one to eating a fish bone.⁵ See bouquet garni and cooking with bay leaves.

Black pepper: the finishing spice

All three recipes season with black pepper, to taste. For grind size, see cracked vs. ground black pepper. It isn’t the only spice in every version: Laurance also adds a little nutmeg.

Nutmeg: an optional warm note

Laurance seasons his soup lightly with salt, “a little pepper and nutmeg.”³ Neither of the other two recipes uses it. A few gratings is plenty. See cooking with nutmeg, and if it takes over, too much nutmeg.

Wine: which kind?

The recipes don’t agree, so here they are side by side:

Recipe	Wine
Saveur (after Patricia Wells)¹	White wine plus sherry
America’s Test Kitchen, via PBS SoCal²	Dry sherry
Bernard Laurance³	Dry white wine

None of the three uses red wine, port or vermouth. White wine, dry sherry or both is the common thread in the recipes we checked.

Stock: beef, chicken, or water

Recipe	Liquid
Saveur¹	Beef stock
America’s Test Kitchen, via PBS SoCal²	Low-sodium chicken broth and beef broth, plus water, some of it for deglazing
Bernard Laurance³	Water with a Maggi stock cube

Beef stock gives the deepest flavor, but ATK’s mix of chicken and beef broth and Laurance’s water-and-cube version both turn up in tested recipes. With store-bought broth or a cube, add salt late and taste first.

Gruyère and the topping

All three recipes top the soup with Gruyère (“the cheese matters!!” for Laurance), and Saveur’s version also adds Parmigiano-Reggiano and lists smashed garlic alongside the baguette.¹²³

When to add each seasoning

From the recipes above:

Sugar (optional): with the onions.
Thyme, bay (or a bouquet garni): with the stock, then simmered. Laurance adds them with the cube and sugar.
Wine or sherry: after the onions have browned and before or with the stock. The exact order varies by recipe, so treat this as a sensible middle path.
Salt, pepper, nutmeg: to taste near the end, especially with salty broth.
Remove the bay leaf and thyme stems before ladling into bowls.

French Onion Soup, Saveur, 2007 (based on Patricia Wells, Bistro Cooking). saveur.com · Publication ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰
Winter Recipe: French Onion Soup, Katherine Spiers, PBS SoCal, 2013 (America’s Test Kitchen recipe). pbssocal.org · Publication ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹
Onion Soup Gratin, Bernard Laurance, La Cuisine de Bernard, 2012. lacuisinedebernard.com · Publication ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹²
Our Guide to Fresh Herbs, Liz Bomze, America’s Test Kitchen, 2019. americastestkitchen.com · Publication ↩
Bay leaves are an optional ingredient, David Leite with J. Kenji López-Alt, The Splendid Table, 2014. splendidtable.org · Publication ↩

Also drawn on

Bouquet garni, Encyclopaedia Britannica. britannica.com
What Is a Bay Leaf, Exactly? (Andrew Coletti, 2023), Atlas Obscura. atlasobscura.com

The Best Seasonings for French Onion Soup: Thyme, Bay, Pepper and What Else Goes In