Jul 14 2026
Restaurants›Union League Cafe›Onion Soup Gratinée Recipe

Onion Soup Gratinée Recipe

Inspired by Union League Cafe
Time1h 15m
Serves4

three onions, three cheeses

Jump to Recipe

Was this page helpful?

Help improve this recipe for others.

Send this recipe to your inbox.

We'll email it straight to you - plus weekly cooking inspiration.

Ingredients

Some product links may be affiliates. If you buy through them, you're supporting the site and Pekin may earn a commission at no extra cost to you.

Soup Base

Gratin Topping

Method

Preparing the Soup

  1. 1

    Cook the Onions

    Peel and thinly slice the yellow onions. In a large pot, heat the olive oil over medium heat. Add the sliced onions and cook, stirring often, until they are soft and caramelized, about 25-30 minutes.

  2. 2

    Add Garlic and Deglaze

    Mince the garlic cloves and add them to the pot. Cook for an additional 2-3 minutes until fragrant. Pour in the dry white wine and scrape any browned bits from the bottom of the pot. Let it simmer for 5 minutes.

  3. 3

    Add Broth and Seasonings

    Add the beef broth, bay leaves, thyme, salt, and black pepper to the pot. Bring the mixture to a boil, then reduce the heat to low and let it simmer for about 30 minutes to allow the flavors to meld.

Preparing the Gratin Topping

  1. 4

    Prepare the Baguette

    While the soup is simmering, slice the baguette into 1-inch thick pieces. Toast the slices in the oven at 350°F (175°C) until golden brown, about 10 minutes.

  2. 5

    Mix the Cheeses

    In a bowl, combine the grated Gruyère, Parmesan, and Fontina cheeses. Set aside.

Assembling and Serving

  1. 6

    Assemble the Soup

    Remove the bay leaves from the soup. Ladle the hot onion soup into oven-safe bowls, filling them about three-quarters full.

  2. 7

    Add the Toast and Cheese

    Place a slice of toasted baguette on top of each bowl of soup. Generously sprinkle the cheese mixture over the bread.

  3. 8

    Broil the Gratin

    Preheat your broiler. Place the bowls on a baking sheet and broil until the cheese is bubbly and golden brown, about 3-5 minutes. Watch carefully to prevent burning.

  4. 9

    Garnish and Serve

    Remove the bowls from the oven and sprinkle with chopped fresh parsley. Serve immediately while hot.

More from Union League Cafe