Ultimate Savory French Onion Green Bean Casserole
Ultimate Savory French Onion Green Bean Casserole
Introduction
Prepare to elevate your holiday table with a sophisticated twist on a beloved classic! Our Ultimate Savory French Onion Green Bean Casserole reimagines the traditional side dish by infusing it with the rich, complex flavors of caramelized onions and Gruyère cheese. This recipe brings tender green beans together with a luscious, savory sauce, creating a truly unforgettable experience that's both comforting and elegantly decadent. Get ready for a new family favorite!
Ingredients
- 3 tablespoons unsalted butter, divided
- 3 large yellow onions, thinly sliced
- 1 teaspoon granulated sugar (optional, for caramelizing)
- Salt and freshly ground black pepper to taste
- 3 cloves garlic, minced
- 3 tablespoons all-purpose flour
- 2 cups beef broth (or vegetable broth for vegetarian option)
- 1 cup heavy cream
- 1 teaspoon fresh thyme leaves, chopped
- 1.5 pounds fresh green beans, trimmed and halved
- 1 cup shredded Gruyère cheese, divided
- 1/2 cup grated Parmesan cheese
- 1/2 cup crispy fried onions (for topping, optional)
Instructions
- Preheat your oven to 375°F (190°C). Grease a 9x13-inch baking dish.
- Caramelize the Onions: In a large, heavy-bottomed skillet or Dutch oven, melt 2 tablespoons of butter over medium-low heat. Add the sliced onions and a pinch of salt. Cook, stirring occasionally, for 25-35 minutes, or until deeply golden brown and very tender. If desired, add the sugar during the last 10 minutes to aid caramelization.
- Add the minced garlic to the caramelized onions and cook for another minute until fragrant. Remove the onions from the skillet and set aside.
- Prepare the Sauce: In the same skillet, melt the remaining 1 tablespoon of butter over medium heat. Whisk in the flour and cook for 1-2 minutes, stirring constantly, until a light roux forms.
- Gradually whisk in the beef broth, ensuring no lumps. Bring the mixture to a gentle simmer, then whisk in the heavy cream and fresh thyme. Cook, stirring frequently, for 5-7 minutes, until the sauce thickens. Season generously with salt and pepper.
- Stir 3/4 cup of the shredded Gruyère cheese and all of the Parmesan cheese into the sauce until melted and smooth.
- Combine & Bake: In a large bowl, combine the trimmed green beans, the caramelized onions, and the creamy cheese sauce. Stir gently to ensure all green beans are coated.
- Pour the mixture into the prepared baking dish. Sprinkle the remaining 1/4 cup of Gruyère cheese over the top.
- Bake for 25-30 minutes, or until the green beans are tender-crisp and the casserole is bubbly and golden brown.
- If using, sprinkle the crispy fried onions over the top during the last 5-10 minutes of baking, or immediately after removing from the oven for maximum crispness.
- Let the casserole rest for 5-10 minutes before serving.
Pro Tips & Notes
- Don't Rush the Onions: True caramelization takes time. Cooking the onions slowly over low heat is key to developing their deep, sweet, savory flavor without burning them.
- Blanch Green Beans: For extra tender green beans, you can blanch them in boiling salted water for 2-3 minutes before adding them to the casserole. This ensures they are perfectly cooked.
- Make Ahead: Assemble the casserole (without the fried onion topping) up to 1 day in advance. Cover and refrigerate. Add an extra 10-15 minutes to the baking time if baking from cold.
- Cheese Swap: If Gruyère is hard to find, a good quality Swiss cheese or even sharp white cheddar can be substituted, though the flavor profile will differ slightly.
- Vegetarian Option: Easily make this vegetarian by using vegetable broth instead of beef broth.
Nutrition Facts (per serving)
- Calories: 380
- Protein: 15g
- Fat: 28g
- Saturated Fat: 16g
- Carbohydrates: 20g
- Fiber: 4g
- Sugar: 8g
- Sodium: 450mg
Frequently Asked Questions
- Q: Can I use frozen green beans? A: Yes, you can use frozen green beans. Thaw them completely and pat them dry before adding them to the casserole to prevent excess moisture.
- Q: What's the best way to store leftovers? A: Store leftover casserole in an airtight container in the refrigerator for up to 3-4 days. Reheat gently in the oven or microwave.
- Q: Can I add mushrooms to this recipe? A: Absolutely! Sauté sliced mushrooms (cremini or button) with the onions or separately and add them to the casserole mixture for an extra layer of umami.
- Q: What if my sauce is too thin? A: If your sauce seems too thin, you can return it to the skillet and simmer it gently for a few more minutes, allowing it to reduce and thicken further. A cornstarch slurry (1 tsp cornstarch mixed with 1 tsp cold water) can also be whisked in for quick thickening.