French onion soup, with its rich, caramelized onions and savory broth, is a culinary masterpiece. But what if you could take that deliciousness and transform it into a comforting, bubbly casserole? This recipe does just that, offering a satisfying twist on a classic that's perfect for a weeknight dinner or a special occasion. Get ready to impress your family and friends with this elevated take on a beloved dish!
What Makes This French Onion Soup Casserole Recipe Special?
This isn't your average casserole. We've focused on creating a recipe that captures the essence of French onion soup while adding the textural delight of a baked casserole. The key lies in the slow caramelization of the onions, building a deep, sweet flavor that forms the foundation of the dish. We then enhance this with a robust beef broth, a touch of dry sherry (optional, but recommended!), and a perfectly browned Gruyère crust. The result is a symphony of flavors and textures that will leave you wanting more.
Ingredients You'll Need:
- For the Caramelized Onions: 3 large yellow onions, thinly sliced; 2 tablespoons olive oil; 1 teaspoon salt; ½ teaspoon black pepper; 1 tablespoon brown sugar (optional, for extra depth of flavor).
- For the Casserole: 6 cups beef broth; ½ cup dry sherry (optional); 2 tablespoons all-purpose flour; 1 teaspoon dried thyme; ½ teaspoon dried rosemary; 1 bay leaf; 8 ounces Gruyère cheese, grated; 1 baguette, sliced into ½-inch thick rounds; 2 tablespoons butter, melted.
Step-by-Step Instructions:
- Caramelize the Onions: This is the most crucial step! Heat olive oil in a large skillet over medium-low heat. Add onions, salt, and pepper. Cook, stirring occasionally, for 30-40 minutes, or until deeply caramelized and golden brown. If using, add brown sugar during the last 10 minutes of cooking for extra sweetness.
- Prepare the Broth: In a large saucepan, whisk together beef broth, sherry (if using), flour, thyme, rosemary, and bay leaf. Bring to a simmer, stirring constantly, until slightly thickened. Remove bay leaf.
- Assemble the Casserole: Preheat oven to 375°F (190°C). In a large oven-safe casserole dish, layer half of the caramelized onions. Pour half of the broth mixture over the onions. Repeat with the remaining onions and broth.
- Bake and Brown: Top with baguette slices, arranging them evenly. Sprinkle generously with grated Gruyère cheese. Drizzle melted butter over the cheese and bread. Bake for 20-25 minutes, or until the cheese is melted, bubbly, and golden brown, and the bread is crispy.
- Serve and Enjoy: Let the casserole rest for a few minutes before serving. This allows the cheese to set slightly, making it easier to serve.
Frequently Asked Questions (FAQs)
Can I use a different type of cheese?
While Gruyère is traditional and provides the best flavor and melt, you can experiment with other cheeses like Swiss, Fontina, or a blend of Gruyère and Parmesan. Just be sure to choose a cheese that melts well.
Can I make this casserole ahead of time?
You can prepare the caramelized onions and the broth mixture a day in advance. Assemble the casserole just before baking. However, for the best results, baking it fresh is recommended.
How can I make this recipe vegetarian?
Substitute the beef broth with a rich vegetable broth. You might also consider adding some sautéed mushrooms to enhance the umami flavor.
What can I serve with this French Onion Soup Casserole?
This casserole is hearty enough to stand on its own, but a simple side salad or some crusty bread would complement it nicely.
Can I freeze this casserole?
It's best to enjoy this casserole fresh, but you can freeze the assembled casserole (before baking) for up to 3 months. Thaw overnight in the refrigerator before baking, adding a few extra minutes to the baking time.
This French Onion Soup Casserole recipe is a guaranteed crowd-pleaser. The combination of sweet caramelized onions, savory broth, and a perfectly browned cheese crust makes for an unforgettable culinary experience. So, gather your ingredients, put on your apron, and prepare to savor the deliciousness!
