Brennan’s French Onion Soup

Brennan’s makes some hearty French onion soup. Onions are gently sauteed in butter, and when caramelized perfectly beef stock is added. Their recipe is slightly different than most onion soups with the addition of an egg yolk and cream for extra richness.

Copycat Brennan's French onion soup in two soup crocks.

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What Makes Brennan’s French Onion Soup So Good? 

In a city that prides itself on tradition, Brennan’s Restaurant stands out as one of those stalwart establishments that ooze old New Orleans charm. After all, one version or another of the restaurant has been the go-to spot for locals and visitors to the city since 1946.

While Brennan’s serves a wide selection of upscale French and Creole-inspired dishes, its unusual take on French Onion Soup has wowed guests for decades. Brennan’s French Onion Soup forgoes the wine and sherry found in traditional recipes but adds eggs and cream for an incredibly decadent dish.

Why You Should Try This Recipe

There aren’t many high-end restaurant recipes on this site, but this New Orleans French Onion Soup recipe from Brennan’s is special. It’s special, not only because of how amazing it tastes, but because it is actually easy to prepare.

There is no reason to feel intimidated by upscale dinner recipes that use terms you aren’t familiar with, such as creating a liaison or tempering. They are just fancy words for easy cooking techniques, and the results are entirely worth it. 

Brennan’s French Onion Soup Ingredients

For this unique take on French Onion Soup, you’ll need the following:

  • Sweet onions
  • Unsalted butter
  • All-purpose flour
  • Beef stock
  • Cayenne pepper
  • Salt
  • Egg yolk
  • Heavy cream
  • French bread
  • Parmesan cheese
Copycat Brennan's French onion soup ingredients on a tray.

Ingredient Notes and Substitutions

With their slightly sweet flavor, Vidalia onions are an excellent choice for making French Onion Soup. Walla Walla onions are another good option. If you can’t find sweet onions, try using white onions with a pinch of sugar.

Substituting light or half & half for the heavy cream in this recipe won’t work. You need the fat content to thicken the soup without separating.

Substituting olive oil for the butter won’t work either. You need the butter’s creaminess and flavor.

You can swap croutons or sauteed breadcrumbs for slices of French bread if you prefer.  

If desired, you can substitute the Parmesan cheese with Swiss or Gruyere.

Add two bay leaves to the soup for additional flavor. Remember to remove them before serving the soup.

How to Make Brennan’s French Onion Soup

To prepare Brennan’s French Onion Soup:

  1. Cut the onions into paper-thin slices. Use a mandolin if you have one; just be careful and use the food guard that came with it. 
  2. Melt the butter in a large soup pot on the lowest setting on your stove. Add the onions and stir well to coat in the butter.
  3. Cook the onions on very low heat until the onions start to break down. Stir occasionally. 
  4. Sprinkle the flour over the onions and stir it in. 
Cooked onion slices in a pan.
Cooked onions and flour mixture in a pan.
  1. While the onions are cooking, melt butter in a small bowl in the microwave. Add the bread crumbs and stir to coat with the melted butter.
  2. Transfer the bread crumbs to a small oven-safe dish, and bake for about 10 to 12 minutes, until they begin to brown and become fragrant. Remove from the oven and set aside
  3. Continue to cook and stir the onions for 10 to 15 more minutes before pouring in the beef stock and adding the cayenne pepper and salt.  
  4. Bring the soup to a boil and reduce it to a simmer for 15 more minutes. Stir from time to time. 
Bread crumbs and melted butter in a bowl.
French onion soup in a pot.
  1. While the soup is simmering, use a whisk to blend the egg and heavy cream together in a small bowl. Reserve for later. 
  2. Remove the pot from the heat. 
  3. Temper the egg and cream mixture by adding a few tablespoons of the hot soup to the bowl while whisking. Raising the temperature will help to prevent the egg from scrambling when you add it to the rest of the soup.
Egg yolk mixture in a bowl.
Egg yolk and onion soup mixture in a bowl.
  1. Pour the warmed egg and cream mixture into the soup pot and stir well. This step, called a Liaison Finale in French, quickly thickens soups and sauces without adding starch.
  2. You can keep the soup warm in a soup kettle, crock pot, or over low heat.
  3. To serve, preheat the oven to broil and ladle the soup into oven-safe bowls. Place the bowls on a baking sheet.
  4. Float slices of French bread on the soup and top the rounds of bread with parmesan cheese and buttered bread crumbs. Melt the cheese under the broiler flame.
  5. If desired, garnish the soup with fresh thyme leaves or other fresh herbs.
Copycat Brennan's French onion soup in two bowls and two spoons.

What to Serve It With This New Orleans French Onion Soup Recipe

This soup is pretty rich, so it’s a good idea to pair it with something that’s on the lighter side. An entree salad is a great choice; perhaps a Cobb salad, spinach salad with warm bacon dressingwedge salad with blue cheese dressing, or Chicken Caesar saladBaked white fish or poached fish is also a good option.

If you are really hungry, then go ahead and make a classic Steak Frites for an authentic French experience. 

How to Store French Onion Soup

If possible, eat this soup the same day you make it. Although you can save leftovers for a few days in an airtight container in the fridge, there’s a good chance the soup will get clumpy and won’t reheat all that well due to the egg and cream in it.

So, if you plan to make the soup in advance, stop preparing the recipe before adding the egg and cream. It will reheat much better.

What’s the Best Way to Reheat French Onion Soup

To reheat a soup already thickened with egg and cream, pour it into a saucepan and add some beef stock or water to thin it out. Heat it gently over medium-low heat while stirring constantly. Garnish the soup with the sliced bread and cheese and finish it in the oven as above. 

If you didn’t add the liaison, simmer the leftovers in a medium saucepan, and thicken the soup with egg and cream as described in the recipe. Finish the recipe as stated.

Overhead view of copycat Brennan's French onion soup in two soup crocks.

More Brennan’s Copycat Recipes

Love onion soup? Try these great recipes!

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Check out more of my easy soup recipes and the best copycat restaurant recipes on CopyKat!

Copycat Brennan's French onion soup in two soup crocks.

Brennan’s Onion Soup

Make Brennan’s French Onion Soup at home with this copycat recipe.
5 from 1 vote
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Course: Soup
Cuisine: French
Keyword: Brennan’s Onion Soup
Prep Time: 10 minutes
Cook Time: 25 minutes
Total Time: 35 minutes
Servings: 8
Calories: 504kcal


  • 16 ounces butter divided use
  • 4 cups sliced onions
  • 1 cup bread crumbs
  • 1 3/4 cups all-purpose flour
  • 12 cups beef stock
  • 1/2 teaspoon cayenne pepper
  • 1 1/2 tablespoons salt
  • 1 egg yolk
  • 2 tablespoons cream
  • 8 slices French bread toasted
  • ½ cup grated Parmesan cheese


  • In a 6-quart soup pot, melt 12 ounces of butter. Add the onions and reduce the heat to very low, ensuring that the onions do not brown. Cook until the onions have caramelized.
  • While the onions are cooking, preheat the oven to 350°F.
  • Melt 4 ounces of butter in a small bowl in the microwave for about 30 seconds on high power. Add the bread crumbs and stir to coat with the melted butter. Transfer the bread crumbs to a small oven-safe dish, and bake for about 10 to 12 minutes, until they begin to brown and become fragrant. Remove from the oven and set aside.
  • When the onions have caramelized, add the flour to the pot and cook for 5 to 10 minutes, stirring occasionally.
  • Add the stock, cayenne, and salt and bring to a boil. Reduce the heat and simmer for about 15 minutes. Remove the pot from the heat.
  • Beat the egg yolk and cream in a small bowl. Add a little of the soup to the bowl and mix quickly. Then add the egg mixture to the soup pot.
  • Ladle the soup into small bowls, place a piece of toasted French bread over each bowl, and sprinkle with the grated Parmesan cheese and buttered bread crumbs. Place the bowls under the broiler until the cheese melts and begins to brown. Serve immediately.


Calories: 504kcal | Carbohydrates: 32g | Protein: 11g | Fat: 37g | Saturated Fat: 23g | Cholesterol: 121mg | Sodium: 2331mg | Potassium: 822mg | Fiber: 2g | Sugar: 5g | Vitamin A: 1205IU | Vitamin C: 5.9mg | Calcium: 67mg | Iron: 2.5mg

About Stephanie Manley

I recreate your favorite restaurant recipes, so you can prepare these dishes at home. I help you cook dinner, and serve up dishes you know your family will love. You can find most of the ingredients for all of the recipes in your local grocery store.

Stephanie is the author of's Dining Out in the Home, and's Dining Out in the Home 2.

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