French Onion Soup Casserole


French Onion Soup Casserole

French Onion Soup Casserole
French Onion Soup Casserole

Why would you make plain old French onion soup when you can make French Onion Soup Casserole? This casserole recipe has all of the best components of traditional French onion soup, but the way it's made changes it into something completely new! Because it's baked in a casserole dish, the bread really soaks up the soup and becomes extremely flavorful. The cheese melts and browns in a perfect layer on top. Best of all, making the soup in a casserole dish makes it so much faster and easier than preparing individual servings.

Serves6 people

Preparation Time10 min

Cooking Time1 hr 30 min


  • 3 medium sweet onions, sliced
  • 3 tablespoons butter
  • 4 cups beef broth
  • 1 teaspoon Worcestershire sauce
  • Approximately 6-8 slices French bread, about 1/2-inch in thickness
  • 1 cup Mozzarella cheese
  • 1/2 cup grated Parmesan cheese


  1. Melt butter in a large saucepan over low heat. Add onions and cover. Cook for about 30 minutes, stirring occasionally.

  2. Add the beef broth and the Worcestershire sauce. Heat the broth mixture until it boils.

  3. Reduce heat to low. All to simmer, uncovered, for about 30 minutes. The broth will reduce.

  4. Pour onion and broth mixture into a greased casserole dish.

  5. Lightly toast the slices of bread. Place toasted bread in a single layer on top of onion/broth mixture.

  6. Cover bread with a thick layer of the shredded mozzarella and top with grated Parmesan.

  7. Place dish under the broiler, watching carefully.  Broil until the cheese melts and begins to brown and bubble.

  8. Let cool for 2-3 minutes. Serve immediately.

Before the French Onion Soup Casserole, There Was Simply a Soup:

Legend has it that the first French Onion Soup was actually created by King Louis the XV of France when all that could be found in the pantry of his hunting party’s lodge was butter, onions, and champagne. While the story cannot be confirmed or denied as myth of fact, it is an interesting bit of lore.

Onions have been a choice staple in meal preparation from as far back Roman Times. This is likely because they are able to easily grow in most soils, they are cheap to buy and abundantly available, not to mention, they long have a high shelf-life. For this reason onions were seen as a poor man's food.

The modern-day version of the French Onion Soup has evolved from a much more basic recipe in which onions were sliced, fried and cooked in water. The soup would then be served with bread and capers. It was only in the 19th century that cooks started adding flour, salt, and pepper and topped the soup with cheeses such as Gruyere.

If you've ever had this classic recipe, you're likely familiar with the present day version. It is most commonly made with caramelized onion in a beef-based broth. This is often served in individual ramekins and topped with Gruyere cheese, which is baked on top.

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DEEEELICIOUS!!! We added extra cheese plus some crushed fresh garlic just because we felt like it but I doubt that it was necessary. A really lovely way to eat French Onion Soup! In our home the adults and teenagers LOVED this French Onion Soup Casserole, the 2 younger ones not so much so my thinking is it is more an adult thing.

I've made this recipe and it was a huge hit! It was so good. I am making it again this evening for a guest who loved it the first time I made it. As for those of you asking what temperature to use. It says broil. That should be a setting on most ovens. Usually means 450-500 degrees and close to heat source. This will require watching closely. Try it and love it!

Don't you just love French Onion Soup? Let's face it, the best part is the crispy, cheese covered French bread, infused with the beefy onion soup flavor. This French Onion Soup Casserole helps you get right to the best part, and still enjoy the rich full flavor of the soup. This is my French Onion Soup recipe from now on.

Has anyone made this yet? In my opinion French onion soup is one of lifes greatest cool weather pleasures. Putting it all into one casserole oven dish sounds like perfection to me. I have a friend, Susanna, who makes an extremely good French onion soup but this absolutely delicious sounding recipe might just match hers. Id love to hear if it is as good as it sounds.and looks!

What a creative way to incorporate the flavors of French onion soup in a casserole. I always wanted to make some French onion soup, but a lot of recipes didn't seem worth the time involved. This recipe looks so effortless that I might actually give this a try. Who wouldn't want to eat slices of French bread infused with the flavors of rich beef broth and onions and topped with gooey, melted mozzarella and Parmesan cheese?

This looks so delicious! Can't wait to try it for dinner on a cold winter night.

Hmmmm, I didn't see a temperature either but the recipe looks so yummy I'm willing to experiment on it anyway. I assumed with the 1 1/2 hour cooking time, that after the simmering of the broth you would use the extra 30 min to bake it. Just a guess but it sounds about right to me. I never thought about French Onion soup as a casserole though...this sounds like a better option than the soup if you're an onion lover like me!

I agree that the recipe ends suddenly. I'm assuming it's baked at 350 degrees until the bread is toasted and the cheese is melted? So, that shouldn't be too long in the oven. Please advise because this looks like a delicious recipe and is a very unique take on French onion soup!

I'm confused too..this recipe ends at #6, it doesn't tell me how long to bake it or on what temperature?


Hi! This recipe calls for 4 cups of beef broth for the moisture element.


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