There’s just something about French Onion Soup that feels like a warm hug from home, isn’t there? The caramelized onions, the gooey melted cheese, that rich, savory broth—it’s no surprise it’s a classic.
Now, picture all those amazing flavors turned into a cozy, shareable casserole that’s even easier to serve. That’s exactly what Southern Living’s French Onion Soup Casserole brings to the table, and food lovers everywhere can’t get enough of it!
This blog will walk you through everything you need to know to create this masterpiece. From the ingredients and essential tools to step-by-step cooking instructions and expert tips, we’ll help you recreate this beloved southern classic in your own kitchen.
Why is this Southern Living French Onion Soup Casserole a Favorite?
The Southern Living French Onion Soup Casserole has gained a devoted following for good reason. It captures the rich, savory essence of traditional French onion soup while transforming it into a hearty, crowd-pleasing dish.
The casserole is great for everything from family dinners to holiday parties because it’s simple to make and serve. Layers of cooked onions, toasted bread, and melted cheese create a delicious flavor that’s warm and satisfying.
The addition of beef broth and aromatic herbs further enhances its appeal, delivering a taste experience that feels both gourmet and familiar. This recipe not only saves time but also brings a new dimension to a well-loved classic.
Ingredients Needed for French Onion Soup Casserole
Here’s what you’ll need to recreate Southern Living’s iconic recipe.
For the Onion Mixture
- 4 large yellow onions, thinly sliced
- 4 tablespoons unsalted butter
- 2 tablespoons olive oil
- 4 cups beef broth (preferably low-sodium)
- 1 teaspoon sugar
- 2 teaspoons fresh thyme leaves (or 1 teaspoon dried thyme)
- Salt and pepper to taste
For the Casserole Base
- 1 loaf of crusty French bread, cut into 1-inch cubes
- 2 cups shredded Gruyère cheese (or your favorite melting cheese)
- 1 cup grated Parmesan cheese
This simple ingredient list ensures you rely on fresh, high-quality components for the maximum depth of flavor.
Essential Equipment for the Recipe
Before starting, make sure you have these tools on hand for a smooth cooking process:
- Large Skillet
- 9×13-inch Baking Dish
- Sharp Knife
- Cutting Board
- Wooden Spoon
- Measuring Cups
- Measuring Spoons
Equipped with these basics, you’re set to start on your culinary adventure.
Step-by-Step Recipe for French Onion Soup Casserole
Now that you have everything ready, here’s how to make the casserole:
Step 1: Get Your Ingredients Ready
Start by slicing the onions nice and thin so they cook evenly and release all that sweet, delicious flavor. Gather the rest of your ingredients—broth, cheese, seasonings—and keep everything within arm’s reach. Trust me, a little prep here will make the cooking process way smoother and save you time later.
Step 2: Caramelize the Onions
Grab a large skillet, heat it over medium, and toss in some butter or oil. Once it’s hot, add your sliced onions and give them a good stir. Let them cook slowly, stirring often, until they turn that perfect golden brown. This can take 20 to 30 minutes, but it’s so worth it—the deep, rich flavor is what makes French onion soup so amazing.
Step 3: Mix It All Together
When your onions are beautifully caramelized, it’s time to add the seasonings and pour in the broth (or any other liquid you’re using). Scrape up all the tasty bits from the skillet and stir everything together. Let it simmer gently so the flavors can blend and fill your kitchen with that mouthwatering aroma.
Step 4: Build the Casserole
Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish to keep things from sticking. Pour the onion mixture into the dish, then top it off with slices of crusty bread or croutons. Don’t be shy with the cheese here—sprinkle it generously over the top to cover everything.
Step 5: Bake It Up
Slide the casserole into the oven and bake until the cheese is melted, bubbly, and just starting to turn golden brown—about 20–25 minutes. This part is pure magic as all those flavors come together into one irresistible dish.
Step 6: Dig In and Enjoy
Take the casserole out of the oven and let it cool for a few minutes (if you can wait that long). Scoop it onto plates or bowls, pair it with a simple salad or your favorite drink, and enjoy the cozy, savory goodness of this French onion soup casserole. It’s comfort food at its finest—bon appétit!
Best Ways to Serve French Onion Soup Casserole
- Serve it as a hearty main dish accompanied by a crisp green salad dressed with a light vinaigrette.
- Pair it with a warm baguette or crusty bread for dipping to soak up the rich, cheesy sauce.
- Offer it alongside a glass of dry white wine or a light red wine to complement the dish’s savory flavors.
- Add a side of roasted vegetables, such as asparagus or green beans, for a more balanced meal.
- Serve it in individual ramekins for an elegant presentation during dinner gatherings.
Tips for Storing and Reheating
- Allow the dish to cool completely before storing it in an airtight container to maintain freshness.
- Refrigerate leftovers promptly and consume them within 2-3 days for the best quality.
- For reheating, use an oven at a low temperature to ensure even warming without overcooking the dish or breaking down delicate textures.
- If reheating in a microwave, cover loosely with a microwave-safe lid or wrap to prevent drying out.
- Avoid freezing dishes with a rich, creamy base, as they may separate once thawed and lose their original consistency.
- Revive the flavors by adding a splash of milk, cream, or stock while reheating to restore the sauce’s creaminess if needed.
Pro Tips for the Perfect French Onion Soup Casserole
I know you can’t wait to try this delicious dish, but here are a few additional tips for making it truly stand out:
- Use freshly grated cheese for the topping to ensure even melting and richer flavor. Pre-shredded cheese often contains additives that can affect texture and taste.
- Caramelize the onions slowly and thoroughly for deep, complex flavors; rushing this step can result in a less robust dish.
- Choose a sturdy bread, like a baguette or sourdough, for the base layer, as it holds up better under the broth and toppings.
- Opt for a combination of beef and chicken stock for a balanced depth of flavor in the broth.
- Bake in an oven-safe dish to achieve a golden-brown, crispy crust with bubbling edges that enhance the casserole’s appeal.
Frequently Asked Questions
Can I use pre-sliced onions or pre-shredded cheese?
For the best flavor, we recommend slicing fresh onions and shredding cheese yourself. Pre-packaged options often compromise on taste and texture.
What can I substitute for Gruyère cheese?
If Gruyère isn’t available, try using Swiss cheese or fontina for a smooth melt and similar flavor profile.
Is the recipe vegetarian-friendly?
Yes, this recipe is vegetarian-friendly as it contains no meat products. However, ensure that the cheese used does not contain animal-derived rennet for a fully vegetarian dish.
Can I prepare this casserole ahead of time?
Yes, you can prepare this casserole ahead of time. Assemble all the ingredients, cover tightly, and store it in the refrigerator for up to 24 hours before baking.
Can I freeze the casserole?
Yes, this casserole can be frozen for future use. Once fully assembled, wrap it tightly with plastic wrap and aluminum foil to prevent freezer burn. It can be stored in the freezer for up to 3 months. When ready to serve, thaw it in the refrigerator overnight before baking.
What are some suitable side dishes to pair with this casserole?
This casserole pairs well with a variety of side dishes. A fresh green salad, roasted vegetables, or garlic bread are excellent options that complement the dish without overpowering its flavors.
Can I make this recipe gluten-free?
Yes, this recipe can be adapted for a gluten-free diet. Simply replace any wheat-based ingredients, such as pasta or breadcrumbs, with certified gluten-free alternatives. Double-check all labels to ensure no hidden sources of gluten.
What substitutions can I make for dietary restrictions?
For a dairy-free option, use plant-based cheese and non-dairy milk instead of cream. To lower the salt, choose low-sodium ingredients and add flavor with herbs and spices.
Conclusion
There you have it! A delicious and easy-to-follow recipe for French onion soup casserole that’s perfect for cozy family dinners, entertaining guests, or just a satisfying meal on a chilly evening. With these step-by-step instructions, helpful tips, and variations to suit your preferences, you’re all set to impress with this savory dish. So go ahead and give it a try – we guarantee it will quickly become one of your favorite go-to recipes! Happy cooking!
Southern Living French Onion Soup Casserole Recipe
Equipment
- Large skillet
- 9×13-inch baking dish
- Sharp Knife
- Cutting board
- Wooden spoon
- Measuring Cups
- Measuring spoons
Ingredients
For the Onion Mixture
- 4 large yellow onions thinly sliced
- 4 tablespoons unsalted butter
- 2 tablespoons olive oil
- 4 cups beef broth preferably low-sodium
- 1 teaspoon sugar
- 2 teaspoons fresh thyme leaves or 1 teaspoon dried thyme
- Salt and pepper to taste
For the Casserole Base
- 1 loaf of crusty French bread cut into 1-inch cubes
- 2 cups shredded Gruyère cheese or your favorite melting cheese
- 1 cup grated Parmesan cheese
Instructions
Step 1: Get Your Ingredients Ready
- Start by slicing the onions nice and thin so they cook evenly and release all that sweet, delicious flavor. Gather the rest of your ingredients—broth, cheese, seasonings—and keep everything within arm’s reach. Trust me, a little prep here will make the cooking process way smoother and save you time later.
Step 2: Caramelize the Onions
- Grab a large skillet, heat it over medium, and toss in some butter or oil. Once it’s hot, add your sliced onions and give them a good stir. Let them cook slowly, stirring often, until they turn that perfect golden brown. This can take 20 to 30 minutes, but it’s so worth it—the deep, rich flavor is what makes French onion soup so amazing.
Step 3: Mix It All Together
- When your onions are beautifully caramelized, it’s time to add the seasonings and pour in the broth (or any other liquid you’re using). Scrape up all the tasty bits from the skillet and stir everything together. Let it simmer gently so the flavors can blend and fill your kitchen with that mouthwatering aroma.
Step 4: Build the Casserole
- Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish to keep things from sticking. Pour the onion mixture into the dish, then top it off with slices of crusty bread or croutons. Don’t be shy with the cheese here—sprinkle it generously over the top to cover everything.
Step 5: Bake It Up
- Slide the casserole into the oven and bake until the cheese is melted, bubbly, and just starting to turn golden brown—about 20–25 minutes. This part is pure magic as all those flavors come together into one irresistible dish.
Step 6: Dig In and Enjoy
- Take the casserole out of the oven and let it cool for a few minutes (if you can wait that long). Scoop it onto plates or bowls, pair it with a simple salad or your favorite drink, and enjoy the cozy, savory goodness of this French onion soup casserole. It’s comfort food at its finest—bon appétit!
