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French Onion Soup Casserole

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This savory French Onion Soup Casserole has all the goodness and flavors of your favorite French onion soup. Sweet caramelized onions, Gruyère cheese, fresh thyme leaves and sourdough French bread. All layered together in a casserole, then soaked with a rich flavorful broth.

French Onion Soup Casserole
Thick with caramelized onions

The very thought of anything involving caramelized onions and I begin drooling. Just imagine what happens when the tantalizing fragrance of simmering onions fills my kitchen!

Our savory bread-base French onion soup casserole is also known as a panade. This type of dish was originally considered as ‘poor man’s food’ and a way of feeding large families with hungry tummies. It incorporated the hard, stale bread with meat and/or vegetables and a liquid to soften the bread and bring it all together.  

What is a Panade?

A panade is a rustic, bread-based casserole made with dry bread, vegetables and/or meat layered together and soaked in a rich, flavorful broth. It usually has a generous chunk of cheese grated between the layers and over the top. It will be soft, creamy and drippy with broth.

close up view of French onion soup casserole
This is so goo!

Is a Panade the Same as a Bread Pudding or a Strata?

A panade, bread pudding, and a strata are similar in that they are all made with stale, dry bread. But the differences are in the liquid used to soak into that dry bread.

  • A panade has a soaking liquid of hot broth, either chicken or beef with maybe some wine mixed into the broth. Hard grated cheese such as Parmesan on top makes a crisp, crunchy top.
  • Bread puddings are usually always sweet desserts. Our Pumpkin Bread Pudding and creamy Bananas Foster Bread Pudding are good examples.  When making bread pudding, the liquid is a combination of sugar, eggs, milk, and cream with the eggs and milk in equal proportions. This makes a soft, custardy interior. Butter brushed on top gives the dessert a nice toasty crust.
  • A strata is also an egg-milk concoction that is savory rather than sweet. There are more eggs than milk to the mixture. There may also be a creamy cheese blended into the mixture like in our Asparagus-Ham and Gouda Breakfast Strata. The high egg/cheese protein makes a strata a great brunch entree.

These old-fashioned bread-based dishes have come full-circle and are now elevated to fashionable status with many creative ideas of deliciousness.

Overhead view of serving, salad, glass of wine and napkin with spoon/fork
Ready for dinner

How to make a French Onion Soup Casserole:

This is a brief overview of the process, please scroll to the recipe card for the full recipe instructions and notes.

The Bread:

We used 10 slices of Francisco International® Extra Sourdough Sliced Bread 24 oz bread. I know this sounds like a lot of bread but after it is dry and toasty from the oven it has a lot less volume and able to absorb the delicious broth.

The Onions:

  • Any type of onions can be used for this casserole, we really like those plain ole yellow onions with the brown skins.  Plus they are the most budget-friendly, too!  
  • It is going to take about 45-60 minutes to get a nice caramelization to the onions. Then take them off the heat and add a good white wine. Be sure to scrape up all the brown bits of onion stuck to the pan bottom, then stir in the fresh thyme leaves. The onions will be savory, sweet and yummy!

The Broth:

  • You will need about two quarts of beef broth as it will soak up into that good sourdough bread.  Heat it up and keep it simmering on a back burner while cooking the onions.  If you have a homemade beef broth it will really enhance the flavor of French onion soup casserole but the canned broth works great as well.  You can also use a canned or homemade chicken broth rather than beef broth.

The Cheese:

  • Gruyère is the classic cheese used for French onion soup and it melts smooth and creamy. The Parmesan cheese adds a tangy taste to the panade casserole. Add the grated cheeses to a bowl and toss them to combine.
French Onion Soup Casserole

Assemble the French Onion Soup Casserole:

Okay, now we are ready to assemble the panade casserole!

  • Be sure to first coat your 9x13x2-inch casserole dish with non-stick spray. Then, add slices of the crisp bread slices to the bottom of the dish in one layer. Break pieces of bread to fill in any spaces so the bottom is covered.  Spoon half of the onions over the bread, then sprinkle a third of the cheese over the onions and season with the pepper.
  • Continue the layering process ending with a layer of bread and reserving the final on third of the cheese.   Gradually ladle the broth on top giving enough time for it to absorb into the bread before adding additional broth pressing down on top with a spatula occasionally.
  • Butter bits are added over the top of the panade and it will bake covered foil and baked for 30 minutes, then the foil is removed and the reserved cheese is added, then back to the oven until the cheese is all gooey and golden brown.

Serve this casserole piping hot in shallow bowls along with a crunchy loaf of garlic bread and a crisp salad.    The classic French onion soup has been transformed!  You’re welcome!  ❤️

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close up view of French onion soup casserole

French Onion Soup Casserole

Yield: 8-10
Prep Time: 1 hour
Cook Time: 55 minutes
Total Time: 1 hour 55 minutes

This savory French Onion Soup Casserole has all the goodness and flavors of your favorite French onion soup. Sweet caramelized onions, Gruyère cheese, fresh thyme leaves and sourdough French bread. All layered together in a casserole, then soaked with a rich flavor broth.


  • 1 large, 24-ounce loaf French sourdough bread, pre-sliced
  • 8 tablespoons (4 ounces) unsalted butter, divided
  • 2 tablespoons extra-virgin olive oil
  • 5 pounds (about 6 large) yellow onions, thinly sliced
  • Sea salt
  • 1/2 cup white wine
  • 1/4 cup fresh thyme leaves
  • 12 ounces Gruyère cheese, grated (about 3 cups)
  • 3 ounces Parmesan, finely grated (about 1 1/3 cups)
  • 5 to 6 cups beef stock
  • Freshly ground white pepper
  • 2 tablespoons butter, cut into small cubes


Preheat the oven to 325°F

  1. Cut the crusts off the bread slices then place the slices in single layers on 2 or 3 sheet pans. Toast the bread for 20 minutes, then flip slices, and rotate pans to ensure even toasting. 
  2. Toast until dried out and lightly golden, about 35-40 minutes total. Set aside. 
  3. Turn oven off until later.

While the bread is toasting:

  1. Set a large Dutch oven or large pot over medium heat. Add 4 tablespoons butter and olive oil. When butter has melted, add onions and 1-1/2 teaspoons salt. Cook covered for 15 minutes, stirring occasionally with a wooden spoon and scraping up bits from the bottom.
  2. Once the onions cook down they will release some liquid, remove lid and increase heat to medium high. Continue cooking and stirring occasionally until onions are golden brown, about 45 minutes total. 
  3. Turn off heat, add the wine and stir to deglaze the pan. Taste, and adjust salt as needed, stir in the fresh thyme leaves and set aside.
  4. Place both cheeses in a medium bowl, and mix to combine.
  5. Heat the oven to 400°F and adjust oven rack to center position.
  6. Coat the inside of a deep 9-by-13-inch baking dish with oil spray. Line the bottom with a layer of toasted bread, breaking up pieces as needed to form a solid layer. 
  7. Spoon half the onion mixture evenly over the bread. Sprinkle with 1/3 of the cheese mixture, and season with pepper. Continue layering with bread, the remainder of the onions and another 1/3 of the cheese. Top off with a final layer of bread.
  8. Ladle 3 cups of hot broth over the panade, then wait a minute, and allow the bread to absorb the liquid. Press down on panade with a metal spatula, add as much broth as the panade will absorb without overflowing. 
  9. Dot the top layer with remaining butter, then cover with a piece of oil-sprayed foil. 
  10. Place casserole dish on a baking sheet to catch any overflow, then transfer to the center rack.
  11. Bake for 30 minutes, then remove foil and sprinkle with remaining 1/3 of cheese and return to oven for 15 minutes more. Bake until golden brown.
  12. Remove casserole from the oven, and allow it to cool for 10 minutes before serving.


  1. You may not need all of the bread slices. We used 10 slices total.
  2. Turn the oven off after toasting the bread. Preheat to 400°f after the onions have cooked.
  3. Allow the panade to rest for 10 minutes before serving.
  4. Reheat any remaining broth and serve in the dish with each portion.
Nutrition Information:
Yield: 8 Serving Size: 1 3x4-inch Square
Amount Per Serving: Calories: 606Total Fat: 36gSaturated Fat: 20gTrans Fat: 0gUnsaturated Fat: 14gCholesterol: 94mgSodium: 1306mgCarbohydrates: 42gFiber: 3gSugar: 7gProtein: 27g

Nutrition information is a guideline only, is calculated automatically by third party software, and absolute accuracy is not guaranteed.

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Pat Nyswonger

Pat is a wife, mom of four adult children, and grandmother to seventeen beautiful children. She is a self-taught home cook and loves creating delicious meals for her family and friends. Her kitchen is the hub of activity in her home, and she loves to entertain.

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