French Onion Soup Casserole is the perfect combination of a classic soup and an easy casserole recipe. This delicious French Onion Casserole is filled with caramelized onions, crunchy baguettes, and plenty of cheese. It tastes just like the soup, but in an easy to make weeknight dinner! I love this easy French Onion Soup Casserole!

french onion soup casserole on a spoon, over a black casserole dish

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Easy French Onion Soup Casserole

What do you get when you combine classic french onion soup with an easy casserole recipe? Easy French Onion Soup Casserole!

French Onion Soup is such a classic, and for good reason. The mixture of flavors is just perfect, and it always feels like such a special treat. I love the slightly sweet yet savory taste of the soup, with croutons and cheese on top. Yum!

Since I’m a fan of easy meals, of course I’m obsessed with casseroles. I wanted to take those amazing flavors from the soup and turn it into an easy casserole recipe that can be made any night of the week! This Easy French Onion Soup Casserole turned out so perfectly, and I think it’s even more crave-worthy than the soup.

You get the delicious caramelized onions, the crispy baguette slices, and lots of cheeeese all mixed together into one dish. I absolutely LOVE this French Onion Casserole!

This easy French Onion Casserole recipe is the perfect blend of flavors!

overhead view of a black casserole dish filled with french onion casserole
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baguette slices topped with caramelized onions and cheese

French Onion Casserole Recipe

What’s not to love about this recipe? An easy french onion soup recipe in the form of an easy to make casserole dish that the whole family will love! Easy, easy, easy (and SO tasty).

Take all of the ingredients and things you love about French Onion Soup, and put them in thus french onion casserole. You get the onions, the crunch, and the cheese! It’s easy to dig in and get the perfect bite with all the flavors melted together.

French Onion Soup Casserole Ingredients:

  • Vidalia Onions
  • Yellow Onions
  • Baguette Slices
  • Thyme
  • Bay Leaf
  • Beef Broth
  • Chicken Broth
  • Gruyere Cheese
  • Dry Sherry
  • Butter
  • Salt & Pepper
french onion soup casserole in a black dish with a serving spoon

How to Make French Onion Casserole

Gather up your ingredients and start making this amazing French Onion Casserole. You can make parts of this recipe ahead of time to help cut down on cook time. The onions can be made up to 3 days ahead, and the baguette slices can be made up to 5 days ahead. That way you can just jump in and bake the casserole when you get home from work and you’re ready to eat!

How to Make French Onion Soup Casserole:

  1. Bake the baguette slices in the oven at 400°F for 8-10 minutes.
  2. While the bread is toasting, add butter, sliced onions, salt & pepper, thyme and bay leaf into a prepared dutch oven. Remove toasted bread from the oven when it’s done.
  3. Place the lid on the dutch oven and cook the onions in the oven at 400°F. After 1 hour, stir the onions and then place them back in the oven, with the lid slightly ajar. Cook another hour.
  4. Now removed the onions from the oven and stir. They should be a dark brown. Cook another 30 minutes if they don’t seem dark enough. You really want to get a nice caramelized flavor out of them.
  5. Transfer the pot of onions to the stove top, and place over medium high heat. Remove the bay leaf.
  6. Add in the sherry, beef broth, and chicken broth. Bring the mixture to a boil, stirring constantly, for about 4-5 minutes until it has thickened.
  7. To make the casserole, layer half of the baguette slices into the casserole dish. Then spoon the onions over each bread slice, and top with the remaining slices. Sprinkle the cheese over everything.
  8. Cover the casserole dish with foil, and bake for 30 minutes at 400°F.
  9. After that, remove the foil, switch the oven to broil, and broil the casserole for about 3 minutes to make the cheese bubbly and golden brown.

Be sure to check the recipe card below for more detailed instructions and the full recipe.

baguette slices topped with cheese and onions in a black baking dish
scooping a piece of french onion casserole out of a black dish

Easy French Onion Recipes

French Onion Soup is good, but I’m a fan of french onion everything. This French Onion Casserole is a new favorite, but I’ve got plenty of other recipes with these amazing flavors! Try my One Pan French Onion Chicken Skillet for the perfect easy chicken recipe. Or make these Mini French Onion Dip Bread Bowl for a fun party appetizer.

casserole dish filled with french onion soup casserole, viewed from the side

I can’t wait for you to try this easy French Onion Soup Casserole because I just know you’ll love it! Make this French Onion Casserole for a delicious dinner and enjoy!

See the recipe card below for details on how to make French Onion Casserole. Enjoy!

If you like this recipe, try these other easy casserole recipes!

Recipe Card

Easy French Onion Soup Casserole

4.68 from 67 votes
Prep: 10 minutes
Cook: 3 hours 15 minutes
Total: 3 hours 25 minutes
Servings: 6 bowls
Author: Becky Hardin
French Onion Soup Casserole is the perfect combination of a classic soup and an easy casserole recipe. This delicious French Onion Casserole is filled with caramelized onions, crunchy baguettes, and plenty of cheese. It tastes just like the soup, but in an easy to make weeknight dinner! I love this easy French Onion Soup Casserole!
French Onion Soup Casserole is the perfect combination of a classic soup and an easy casserole recipe. This delicious French Onion Casserole is filled with caramelized onions, crunchy baguettes, and plenty of cheese. It tastes just like the soup, but in an easy to make weeknight dinner! I love this easy French Onion Soup Casserole!
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Ingredients 

  • 16 ounces baguette cut into ¼-inch slices (1 loaf)
  • ¼ cup unsalted butter (½ stick)
  • 2 Vidalia onions halved and cut top-to-bottom into ¼-inch-slices
  • 3 yellow onions halved and cut top-to-bottom into ¼-inch-slices
  • 1 teaspoon kosher salt
  • ½ teaspoon freshly ground black pepper
  • 5 fresh thyme sprigs leaves removed
  • 1 bay leaf
  • ½ cup dry sherry
  • 1 cups unsalted beef broth
  • 2 cups unsalted chicken broth
  • 8 ounces freshly shredded Gruyere cheese (about 2 cups)

Instructions 

  • Preheat oven to 400°F and set the oven rack to the lower-middle position. Spray a 9×13-inch baking dish with nonstick cooking spray and set aside.
  • Place the baguette slices on a metal rack placed inside a baking sheet and bake for 8-10 minutes or until golden brown. Remove from the oven and set aside until ready to use.
    16 ounces baguette
  • While the bread slices toast, generously spray the inside of a large Dutch oven with nonstick cooking spray. Slice the onions (if they haven’t already been sliced).
    2 Vidalia onions, 3 yellow onions
  • Add the butter, sliced onions, salt, black pepper, thyme leaves and bay leaf to the Dutch oven.
    ¼ cup unsalted butter, 1 teaspoon kosher salt, ½ teaspoon freshly ground black pepper, 5 fresh thyme sprigs, 1 bay leaf
  • Once the baguette slices have toasted, cover the Dutch oven tightly and cook the onions 1 hour. Remove pot from oven and stir, being sure to scrape the sides and bottom of pot.
  • Return the pot to the oven with the lid slightly ajar and continue cooking another 1 hour.
  • Once again, remove the pot from the oven and stir the onions (scraping the sides and bottom). The onions will be soft and a little darker than golden brown. If the onions need more color, return the pot to the oven (still with the lid slightly ajar) and cook another 30 minutes.
  • Transfer the pot to the stovetop and turn the heat to medium-high. *Remember – the pot is HOT! Use oven mitts when touching the handles.*
  • Remove and discard the bay leaf from the onions.
  • Add sherry, beef broth and chicken broth; bring to a boil, stirring constantly, until slightly thickened, about 4-5 minutes.
    ½ cup dry sherry, 1 cups unsalted beef broth, 2 cups unsalted chicken broth
  • Layer half the toasted baguette slices in the prepared casserole dish.
  • Spoon onion mixture evenly over the bread, and top the remaining bread slices.
  • Sprinkle with shredded cheese and cover with foil.
    8 ounces freshly shredded Gruyere cheese
  • Bake at 400°F for 30 minutes.
  • Set the heat to broil and remove the foil.
  • Broil 3 minutes or until cheese is bubbly. Watch closely.
  • Garnish with additional thyme leaves, if desired.

Video

Becky’s Tips

  • The baguette slices can be made up to 5 days ahead and kept in an airtight container until ready to use.
  • The caramelized onions can be made up to 3 days ahead and kept refrigerated, in an airtight container, until ready to use.
Storage: Store leftover French onion soup casserole in an airtight container in the refrigerator for up to 4 days.
Serving: 1bowlCalories: 510kcalCarbohydrates: 52gProtein: 22gFat: 23gSaturated Fat: 13gPolyunsaturated Fat: 2gMonounsaturated Fat: 6gTrans Fat: 0.3gCholesterol: 62mgSodium: 1235mgPotassium: 508mgFiber: 4gSugar: 12gVitamin A: 638IUVitamin C: 11mgCalcium: 508mgIron: 3mg

Nutrition information is automatically calculated, so should only be used as an approximation.

Did you make this? Leave a comment!

Meet Becky Hardin

Becky Hardin is a wife and mother living in Saint Louis Missouri. She founded The Cookie Rookie in 2012 as a creative way to share recipes. Now, she is a trusted resource for easy cooking around the world, being featured in Taste of Home, The Kitchn, ABC’s Home and Family, and more. Here at The Cookie Rookie she is the editor in chief of all recipes and continues to enjoy sharing her passion for cooking for busy families. She has since founded two additional food blogs, Easy Chicken Recipes and Easy Dessert Recipes.

4.68 from 67 votes (60 ratings without comment)
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24 Comments
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Jim Jones
Jim Jones
September 6, 2023 10:02 am

Darn Jenny you forgot to bit*h about the time to cut the onions, grade the cheese, slice the bread………

Samantha Marceau
May 8, 2023 9:16 am

Hi Jenny, we apologize for the confusion. We are in the process of updating many of our older recipes. The timing for this recipe reflected active cook time, not the total passive cook time. It has been updated!