If you have a craving for something cozy yet elegant, this French Onion Soup Casserole Recipe is a must-try comfort dish that transforms classic French onion soup into a hearty, baked delight. Imagine the rich, caramelized onions mingling with creamy soup base, topped with toasted French bread and golden melted Swiss cheese—all baked together to perfection. It’s the perfect meal to warm your soul any day of the week, and I’m excited to share how you can easily make it at home.
Ingredients You’ll Need
Gathering the right ingredients is key to creating the rich flavors and satisfying textures in this French Onion Soup Casserole Recipe. Each component plays an important role: onions bring sweetness, Swiss cheese offers creaminess and meltiness, and the French bread adds that irresistible crunch. Here’s what you’ll need:
- 2-3 tablespoons butter or margarine: This is essential for sautéing the onions until they develop that lovely golden color and deep flavor.
- 3 large sweet onions or 4 medium white or yellow onions: Onions are the heart of this dish, and the choice affects the sweetness and aroma.
- 2 cups shredded Swiss cheese (8 oz.): Swiss cheese melts beautifully and adds a nutty, creamy dimension.
- 1 can cream of chicken soup, undiluted (or cream of mushroom soup for vegetarian): This gives the casserole a rich, comforting base and binds everything together.
- 2/3 cup milk: Added to lighten the soup mixture and achieve a luscious texture.
- 1 teaspoon soy sauce: Just a touch to deepen the flavor with a subtle umami twist.
- 8 slices of French bread: Classic choice for topping that crisps up during baking, giving the casserole great texture contrast.
- Pepper to taste: Adds a gentle kick that balances the savory flavors.
How to Make French Onion Soup Casserole Recipe
Step 1: Prepare the Onions
Start by peeling and slicing your onions thinly. Yes, it might cause a few tears, but it’s all worth it! The onions are what bring that incredible sweetness and depth to this dish.
Step 2: Sauté the Onions
In a medium sauté pan, melt the butter over medium heat. Add your sliced onions and cook them gently until they turn transparent and just begin to brown. This slow cooking process releases their natural sugars, transforming them into caramelized perfection that’s full of flavor.
Step 3: Layer the Casserole
Grab a shallow 2-quart casserole dish to start layering. Begin with a bed of those tender sautéed onions, sprinkle about two-thirds of your shredded Swiss cheese evenly, and add pepper to taste for that subtle bite. The cheese melts into the layers, giving the casserole that creamy richness we all love.
Step 4: Combine the Soup Mixture
In a small saucepan, warm the undiluted cream of chicken soup with the milk and soy sauce, stirring thoroughly until silky smooth. Pour this mixture over the onion and cheese layers in the casserole and gently stir to combine everything just a bit. This step gives the dish moisture and a flavorful sauce that ties all the ingredients together.
Step 5: Top with French Bread and Bake
Arrange the slices of French bread on top of your casserole. Slide the dish into a preheated oven at 350°F (175°C), uncovered, and bake for 15 minutes until the bread turns beautifully toasted and slightly crisp. This layer will add texture and soak up some of the delicious juices beneath.
Step 6: Add Remaining Cheese and Final Bake
After the first bake, gently press the bread slices down into the savory sauce and sprinkle the remaining Swiss cheese over the top. Return the casserole to the oven and bake for an additional 15 minutes until the cheese melts into bubbly, golden goodness. This final step brings everything together into one incredible, mouthwatering dish.
How to Serve French Onion Soup Casserole Recipe
Garnishes
Sprinkle freshly chopped thyme or parsley over the top before serving to add a pop of color and a delicate herbal aroma. A light drizzle of extra virgin olive oil can also enhance the richness if desired.
Side Dishes
This casserole pairs wonderfully with a crisp green salad or roasted vegetables to bring some fresh crunch and balance to the creamy, cheesy casserole. A glass of white wine, like Chardonnay, makes a lovely companion if you’re feeling indulgent.
Creative Ways to Present
For a charming, rustic presentation, serve individual portions in small ramekins or mini cast-iron skillets. Toast some extra French bread slices on the side to create little dipping scoops and make the meal interactive and fun!
Make Ahead and Storage
Storing Leftovers
If you’re lucky enough to have leftovers, store them in an airtight container in the refrigerator for up to 3 days. The flavors meld nicely overnight, making the next-day taste just as satisfying.
Freezing
This French Onion Soup Casserole Recipe freezes well before the final bake. Just prepare through the first bake with the bread on top, then cover tightly and freeze. When ready, thaw overnight in the fridge, add the remaining cheese, and bake as directed for the perfect fresh experience.
Reheating
Reheat leftovers covered in the oven at 350°F (175°C) until warmed through and the cheese is melty again—about 20 minutes. You can also use a microwave in a pinch, though the crust will lose some crispness.
FAQs
Can I use different types of cheese?
Absolutely! While Swiss cheese is traditional and melts beautifully, Gruyère or mozzarella can be delicious alternatives if you want to experiment or don’t have Swiss on hand.
Is this recipe suitable for vegetarians?
Yes, just swap the cream of chicken soup for cream of mushroom soup, and you have a vegetarian-friendly casserole that’s just as comforting and flavorful.
Can I make this gluten-free?
Definitely! Simply replace the French bread with gluten-free bread slices. The dish will retain all its deliciousness without the gluten.
What if I don’t have soy sauce?
If you’re out of soy sauce, a splash of Worcestershire sauce or a pinch of salt can work to add that umami depth, though the flavor profile may vary slightly.
How spicy is the casserole?
This casserole is mild and savory, with a gentle peppery bite if you add pepper to taste. It’s perfect for those who prefer comfort food without heat.
Final Thoughts
There’s something truly special about this French Onion Soup Casserole Recipe that feels like a warm hug in food form. Whether you’re cooking for family or friends, it’s a dependable crowd-pleaser that brings rich flavor and satisfying textures to the table. Give it a try—you might just find a new favorite to make over and over again!
Print
French Onion Soup Casserole Recipe
- Prep Time: 15 minutes
- Cook Time: 30 minutes
- Total Time: 45 minutes
- Yield: 6 servings
- Category: Casserole
- Method: Baking
- Cuisine: French American
Description
This French Onion Soup Casserole is a comforting and hearty dish combining the deep flavors of sautéed onions with creamy cheese and a savory soup base, topped with toasted French bread and melted Swiss cheese. Perfect for a cozy dinner, it layers sweet onions, creamy soup, and bread for a casserole that captures the essence of traditional French onion soup in an easy-to-make format.
Ingredients
For the Onions and Casserole Base
- 2–3 tablespoons butter or margarine
- 3 large sweet onions or 4 medium white or yellow onions
- 2 cups shredded Swiss cheese (8 oz.)
- 1 can cream of chicken soup, undiluted (or cream of mushroom soup for vegetarian)
- 2/3 cup milk
- 1 teaspoon soy sauce
- Pepper to taste
Topping
- 8 slices French bread
Instructions
- Prepare the Onions: Peel and slice the onions carefully, aiming to minimize crying by slicing near a vent or under running water.
- Sauté the Onions: In a sauté pan, melt 2-3 tablespoons of butter over medium heat. Add the sliced onions and cook, stirring occasionally, until they become translucent and tender with a little browning, which will enhance their sweetness and flavor.
- Layer the Casserole: In a shallow 2-quart casserole dish, spread a layer of the sautéed onions, then sprinkle 2/3 of the shredded Swiss cheese over the onions. Add pepper to taste to season the layers.
- Make the Soup Mixture: In a saucepan, combine the can of cream of chicken soup, 2/3 cup milk, and 1 teaspoon soy sauce. Heat gently while stirring until the mixture is blended and warm but not boiling.
- Combine Layers: Pour the warm soup mixture over the layered onions and cheese in the casserole dish. Stir gently to distribute the soup evenly through the layers.
- Top with Bread: Arrange the 8 slices of French bread evenly on top of the casserole surface. Then place the casserole uncovered in an oven preheated to 350°F (175°C) and bake for 15 minutes until the bread is nicely toasted.
- Add Remaining Cheese: Remove the casserole from the oven and press the bread slices slightly into the sauce. Sprinkle the remaining 1/3 of Swiss cheese evenly over the bread slices.
- Final Bake: Return the casserole to the oven and bake for an additional 15 minutes until the cheese topping is melted, bubbly, and lightly golden, ensuring a rich and cheesy finish.
Notes
- You can substitute cream of mushroom soup to make this vegetarian-friendly.
- Use day-old French bread for better toasting and texture.
- For a richer flavor, caramelize the onions longer to develop deeper sweetness and color.
- Adjust pepper according to your taste preferences.
- Leftovers can be refrigerated and reheated, though bread topping is best fresh.
