French onion green bean casserole is a rich, savory twist on classic green bean casserole with tender green beans baked in a creamy onion sauce and topped with melty Gruyère and crisp croutons. It has all the comfort of the holiday classic, but with deeper flavor from slowly cooked onions.
A Quick Look at the Recipe
✅ Recipe Name: French Onion Green Bean Casserole
🕒 Ready In: ~1 hour
👪 Serves: 8
🍽 Calories: ~290 per serving (estimated)
🥣 Main Ingredients: Green beans, onions, butter, chicken broth, heavy cream, Gruyère, croutons
📖 Dietary Info: Vegetarian option, gluten-free option
👌 Difficulty: Medium - caramelize then bake
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This version leans into that French onion soup style flavor, so it feels a little more special than the usual shortcut casserole. The onions cook down until soft and golden, which gives the sauce a richer, sweeter base that pairs perfectly with the green beans.
If you want more cozy holiday sides, try our Pecan Sweet Potato Casserole, Creamed Spinach, Mashed Butternut Squash, or Sourdough Stuffing.
Jump to:
- A Quick Look at the Recipe
- Why You'll Love French Onion Green Bean Casserole:
- Key Ingredients:
- Easy Substitutions & Variations:
- How to Make French Onion Green Bean Casserole:
- Recipe Notes & Tips:
- How to Store:
- French Onion Green Bean Casserole FAQs:
- More Side Dish Recipes You'll Love
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- French Onion Green Bean Casserole
Why You'll Love French Onion Green Bean Casserole:
Deep French Onion Flavor: Slowly cooked onions give the casserole a rich, savory flavor that tastes more special than a classic version.
Creamy and Cheesy: The broth, cream, and Gruyère create a sauce that feels cozy and extra satisfying.
Holiday Worthy Side Dish: It's a great option when you want a green bean casserole that feels homemade and a little more elevated.
Great Texture: Tender green beans, soft onions, melty cheese, and crisp croutons give every bite something different.
Key Ingredients:
- fresh green beans. Keep the casserole fresh and tender, and they hold their texture better than canned beans.
- onions. The star of the recipe, adding the sweet savory flavor that gives the casserole its French onion character.
- chicken broth. Helps create the savory sauce base, and homemade chicken broth works especially well here for deeper flavor.
- heavy cream. Adds richness and gives the casserole its creamy texture.
- gruyère cheese. Adds rich, melty flavor that pairs perfectly with the onions.
- croutons. Add a crisp topping that gives the casserole extra texture.before serving.
Scroll to the recipe card at the bottom of this page for exact quantities.
Easy Substitutions & Variations:
- Vegetarian option: Use vegetable broth instead of chicken broth.
- Gluten-free option: Use a gluten-free flour blend in place of flour and use gluten-free croutons, or swap croutons for a crispy gluten-free topping.
- Cheese swap: Swiss works if you do not have Gruyère, or use a mix of Swiss and mozzarella for a milder flavor.
- Make it extra oniony: Add a small splash of balsamic vinegar while the onions cook to deepen the flavor.
- Make ahead: Assemble the casserole without the croutons, refrigerate, then add the croutons right before baking so they stay crisp.
How to Make French Onion Green Bean Casserole:
- Step 1: Preheat the oven to 375°F and grease a 9×13 baking dish. Bring a large pot of salted water to a boil. Add the green beans and cook for 4 to 5 minutes, just until bright green and slightly tender. Drain and set aside.
- Step 2: In a large skillet, melt the butter over medium heat. Add the sliced onions and cook, stirring often, until softened and golden, about 20 to 25 minutes.
- Step 3: Add the garlic and cook for about 30 seconds, just until fragrant. Sprinkle in the flour, salt, and pepper, then stir well to coat the onions.
- Step 4: Slowly pour in the chicken broth and heavy cream, stirring until smooth. Simmer for 2 to 3 minutes, until slightly thickened.
- Step 5: Add the green beans and half of the Gruyère, then stir until combined.
- Step 6: Transfer the mixture to the baking dish and top with the remaining Gruyère and the croutons. Bake for 20 to 25 minutes, until hot and bubbly.
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Recipe Notes & Tips:
- Do not overcook the green beans: Blanching them just until bright green keeps them tender crisp after baking.
- Take your time with the onions: Cook them until soft and golden so the casserole has real French onion flavor.
- Stir well after adding flour: Coating the onions evenly helps the sauce thicken smoothly.
- Add broth slowly: Pouring in the broth gradually prevents lumps and makes the sauce silky.
- Add croutons at the end if needed: If your oven runs hot, add the croutons during the last 10 minutes so they do not get too dark.
How to Store:
Refrigerator: Store French onion green bean casserole in an airtight container for up to 4 days.
Reheat: Warm in a 350°F oven until heated through for the best texture. The microwave works too, but the topping will soften.
Make ahead tip: If making ahead, store the croutons separately and add them before reheating or baking so they stay crisp.
French Onion Green Bean Casserole FAQs:
To keep French onion green bean casserole from being watery, blanch the green beans briefly and drain them well. Cooking the onions with flour and simmering the broth and cream until slightly thickened also helps the sauce set up properly.
Yes, you can assemble French onion green bean casserole ahead of time and refrigerate it. For the best crunch, add the croutons right before baking.
Gruyère is one of the best cheeses for French onion green bean casserole because it melts well and pairs perfectly with caramelized onions. Swiss cheese is a good substitute if needed.
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French Onion Green Bean Casserole
Ingredients
- 2 pounds fresh green beans
- ¼ cup butter
- 4 medium onions, sliced
- 3 garlic cloves, minced
- ¼ cup flour
- ½ teaspoon salt
- ¼ teaspoon pepper
- 1 ½ cups chicken broth
- ½ cup heavy cream
- 1 ½ cups gruyere, shredded
- 1 cup croutons
Instructions
- Preheat the oven to 375°F and grease a 9×13 baking dish.
- Bring a large pot of salted water to a boil. Add the green beans and cook for 4 to 5 minutes, just until bright green and slightly tender. Drain and set aside.
- In a large skillet, melt the butter over medium heat. Add the sliced onions and cook, stirring often, until softened and golden, about 20 to 25 minutes.
- Add the garlic and cook for about 30 seconds, just until fragrant.
- Sprinkle in the flour, salt, and pepper, then stir well to coat the onions.
- Slowly pour in the chicken broth and heavy cream, stirring until smooth. Simmer for 2 to 3 minutes, until slightly thickened.
- Add the green beans and half of the Gruyère, then stir until combined.
- Transfer the mixture to the prepared baking dish and top with the remaining Gruyère and the croutons.
- Bake for 20 to 25 minutes, until hot and bubbly and the topping is lightly golden.
Nutrition
Notes
- Do not overcook the green beans: Blanching them just until bright green keeps them tender crisp after baking.
- Take your time with the onions: Cook them until soft and golden so the casserole has real French onion flavor.
- Stir well after adding flour: Coating the onions evenly helps the sauce thicken smoothly.
- Add broth slowly: Pouring in the broth gradually prevents lumps and makes the sauce silky.
- Add croutons at the end if needed: If your oven runs hot, add the croutons during the last 10 minutes so they do not get too dark.
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