There’s nothing quite like French onion soup—the deep golden onions, the rich broth, the cheesy, bubbling bread on top. But this version gets a subtle twist that makes it extra special: miso. Just a couple tablespoons of white miso paste adds that savoury, umami depth that tastes like the soup has been simmering for hours (even though it only takes less than an hour start to finish).

This Miso French Onion Soup is one of those recipes that feels cozy and comforting but also just a little fancy—perfect for a cold night in or when you want to impress without overcomplicating things. Toasted sourdough, plenty of melty cheese, and fresh thyme tie it all together into a bowl you’ll want to come back to again and again.

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Why You’ll Love this Recipe:

• Quick but rich: All the deep, slow-cooked flavour of classic French onion soup in just 40 minutes.
• Unexpected miso: White miso adds a savoury, umami depth that makes the broth taste like it’s been simmering all day.
• Cozy yet chic: Feels restaurant-worthy with the golden, cheesy top but simple enough for a weeknight.
• Customizable: Use any melty cheese you love and swap in your favourite bread for the perfect finishing touch.

Ingredients for Miso French Onion Soup:

Onions: The star of the show. Yellow onions are best here for their balance of sweetness and savouriness once caramelized.

Butter + olive oil: Butter adds richness, while olive oil helps keep the onions from burning as they cook low and slow.

Salt: A generous pinch at the start helps the onions break down and release their natural sweetness.

Garlic (optional): Fresh cloves, minced, to build extra flavour with the onions.

White wine: Used to deglaze the pot, scraping up all those caramelized bits for extra depth. A dry white like Sauvignon Blanc, Pinot Grigio, or Chardonnay works beautifully. Just use extra broth if you want to skip the wine.

Bone broth: Beef or chicken bone broth are great for getting the deepest flavour. Regular beef or chicken stock/broth work too, or vegetable broth if you want to keep it vegetarian.

White miso paste: Adds a delicate umami richness that makes the soup taste like it’s been simmering all day.

Fresh thyme + a bay leaf: This duo infuses the broth with an herby and lightly earthy taste—don’t skip it!

Sourdough bread: Your base for that signature cheesy top. Toast it first (in your toaster or with olive oil in the oven) so it holds up to the broth.

Gruyère cheese: A classic for French onion soup—melts beautifully and brings nutty, salty flavour. Comté or another melty cheese will work too.

Prep for Miso French Onion Soup:

There’s not much prep for this one at all!

• Slice all of the onions up thinly so that they caramelize evenly.
• Mince the garlic if you’re using some.
• Rinse your fresh thyme, saving some for garnishing at the end.
• Grate the cheese and don’t forget to toast up your bread before assembling the bowls of soup.

How to Make Miso French Onion Soup:

Step One:

In a large pot, melt down the butter with the olive oil. Add the sliced onions, along with some salt, and sauté on medium-low heat for about 20 minutes until golden brown and caramelized. Optional: add in some minced garlic when the onions are almost done caramelizing.

Step Two:

Deglaze with the white wine, stirring to scrape up all the browned bits.

Step Three:

Add the bone broth, miso paste, a few sprigs of fresh thyme, and a bay leaf. Simmer for 15 minutes.

Step Four:

Remove the herbs and then ladle the soup into oven safe bowls or crocks.

Step Five:

Toast up some sourdough, then brush lightly with olive oil. Top each bowl with a piece of the toasted bread and plenty of grated cheese.

Step Six:

Place the soups under the broiler until golden and bubbly (I like putting them all on one sheet pan for ease). Garnish with some extra fresh thyme!

Substitutions for Miso French Onion Soup:

Onions: Yellow onions are the classic choice for their perfect blend of sweetness and brightness. Red onions, sweet onions (like Vidalia), white onions, or shallots can also work, but each variety will yield a different flavour.

Butter: You can caramelize the onions in extra olive oil if you want to skip the butter.

Bone broth: Chicken or beef bone broth works for a nice deep flavour. You can also use traditional broth/stock, including veggie stock.

White miso paste: Red or brown miso paste will also add that umami flavour, but you’ll want to use less/taste as you go as they are saltier than white miso paste is.

Fresh thyme: A sprinkle of dried thyme or even Italian seasoning can work in a pinch, but the flavour and aroma the fresh thyme adds is so nice!

Cheese: I went with gruyère, but any cheese works here as long as it melts nicely—comté, mozzarella, or gouda are good picks.

Sourdough bread: Any crusty, toasted bread, like ciabatta or a French baguette, will work nicely here if you don’t have sourdough.

How to Store 

To best save any leftovers, I recommend saving the base soup on its own, as the assembled soups with bread and melted cheese won’t hold up well in the fridge/freezer.

Fridge:
Let the soup cool completely, then transfer to an airtight container. Store in the fridge for up to 4 days. Heat gently on the stove, then ladle into oven-safe bowls. Top with fresh toasted bread + grated cheese, then broil.

Freezer:
Let the soup cool completely, then transfer to a freezer-safe container. Store in the freezer for up to 3 months. Thaw in the fridge overnight, then heat gently on the stove and ladle into oven-safe bowls. Top with fresh toasted bread + grated cheese, then broil.

French onion soup, but kicked up an extra savoury notch. Tag me on social if you try it out, @britacooks. I’d love to see all of your soups! xx