Onion Soup Gratinée

This soup is not mine. I wish it were because it might be the best thing I’ve ever eaten. I had always loved French Onion soup. So it was no surprise when my friend took me to a French restaurant in Soho called Balthazar that I ordered their Onion Soup Gratinée. These were my pre-vegan days, of course, and for weeks afterward, I only dreamt of this soup. It was so unbelievably satisfying that I finally reached out to my friend Kate and asked her to get me the Balthazar cookbook. The day I got the book in the mail, I went to the store, bought a 3-pound bag of onions, and went to work.

Now that I’m vegan, there were only a few small modifications to make. I am thrilled to say the flavor has not been altered at all. The trick is to make sure that the onions are deeply caramelized. Cooking the onions may take longer than expected, about 40 minutes. Be sure to keep the heat at medium and stir frequently. You do not want the onions to burn. The other key to this soup is the cheese. I used Miyoko’s Mozzarella cheese and grated it over the toasted sourdough bread.

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Onion Soup Gratinée

  • Author: Stephanie Bosch


A quote from the Balthazar’s cookbook…”Borrow a custom from Bordeaux and spill a little red wine into the bottom of your nearly empty soup bowl.  The tradition, down known as chabrot, dictates a quick swirl of wine into the tail-end of the hot broth and then a hearty gulp right from the bowl.” 


  • 1/4 cup plus 1 tablespoon olive oil
  • 4 medium yellow onions, peeled, halved through the stem end, and sliced 1/4 inch thick
  • 1 tablespoon unsalted vegan butter
  • 1 garlic clove, peeled and thinly sliced
  • 4 sprigs of thyme
  • 1 bay leaf
  • 1 tablespoon salt
  • 1/4 teaspoon freshly ground white pepper
  • 3/4 cup dry white wine
  • 2 quarts vegetable stock
  • 1/2 cup port
  • 6 slices of sourdough bread, about 1 inch thick, toasted
  • 2 cups Miyoko’s vegan mozzarella, coarsely grated.


In a 5-quart Dutch oven or other large, heavy pot, heat the olive oil over a medium flame. Add the onions and, stirring frequently to prevent burning, sauté until they reach a golden color, approximately 30 minutes.

Add the butter, garlic, thyme, bay leaf, salt, and pepper and cook for 10 minutes. Raise the heat to high, add the white wine, bring to a boil, and reduce the wine by half, about 3 to 5 minutes.

Add the vegetable stock and simmer for 45 minutes. Preheat the broiler. Remove the thyme springs and bay leaf, and swirl the port into the finished soup.

Ladle the soup into the 6 ovenproof bowls.

Fit the toasted bread into the bowls on top of the liquid, and sprinkle 1/3 cup of Mozzarella onto each slice. Place under the broiler for 3 minutes, or until the cheese melts to a crispy golden brown. Allow the soup to cool slightly, about 3 minutes, before serving.

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