A savory side dish inspired by everything I love about French onion soup–caramelized onions, crunchy bread, and alllll the cheese made into a French Onion Soup Casserole.
A cold winter evening at home is made into something really special with the addition of a dinner that’s rustic, elegant, yet simple to pull off. This French Onion Soup Casserole brings all those soup vibes, yet it’s simpler to pull off as it all bakes in one pan. No individual ramekins of soup or broiling involved. Instead, everything bakes together and no one skimps on the cheese.
This French Onion Soup Casserole is part of my Romantic Winter Dinner Menu for Two, which leans into rustic elegance and celebrates a cozy dinner with a loved one. It’s comforting and unfussy: a savory skillet dinner, cozy sides, and a dessert meant to be shared straight from the pan. This casserole is the most decadent part of the meal…and probably the most memorable.
A favorite soup transformed
There’s something so comforting about a casserole. It’s a dish meant to be shared and everyone can have a slice. For my Romantic Winter Dinner Menu, it made sense to have a shared dish that served as a side rather than individual bowls of soup. The casserole feels especially cozy and perfect for a meal by the fireplace.
The other simple element of this casserole is that it can be made ahead, making dinner time even easier. Just caramelize the onions and assemble during the day. Then bake it off while dinner comes together. It makes enjoying time in the kitchen with a loved one even more fun.
French Onion Soup Casserole
Course: SidesCuisine: AmericanDifficulty: Easy4
servings10
minutes40
minutesIngredients
3 Tbsp butter
3 Tbsp olive oil
4 large onions, thinly sliced
1 tsp salt
1/2 tsp pepper
1 tsp sugar
2 cloves garlic, minced
1 Tbsp thyme leaves, minced
1/2 cup dry white wine
1 Tbsp flour
1 cup beef or vegetable broth
1 baguette, cubed
2 cups shredded gruyere
1/2 cup grated parmesan
Directions
- Preheat the oven to 375ºF. Prepare and grease a 9×13″ baking pan. Set aside.
- Start by caramelizing the onions. Heat butter and olive oil in a large skillet over medium heat. Add onion slices, salt, pepper, and sugar. Cook for 30-35 minutes until deeply golden brown. Once caramelized, add in garlic and thyme and stir for 1 minute until fragrant. Add wine and cook until evaporated. Sprinkle in the flour and cook 1 more minute. Add in the broth and simmer 3 minutes until thickened. Transfer to the bottom of the 9×13″ pan.
- While the onions are caramelizing, toast the bread cubes. Spread the bread cubes on a baking sheet and drizzle with olive oil. Massage the olive oil into the cubes using a spoon or your hands. Bake for 10-12 minutes, until lightly toasted. Don’t over-brown.
- Add the toasted bread on top of the caramelized onions. Then scatter the gruyere and Parmesan on top.
- Bake for 15-20 minutes on the cheese is melted and bubbling. Let stand 5 minutes, then serve and enjoy!
How I Serve It
I love choosing a special casserole dish to bake this in so it can be served directly out of the pan. Serve it hot from the oven to get the most impressive cheese pull for your guests. A sprinkle of thyme on top is really all this needs. Any leftovers will be perfect for lunch tomorrow.
Make it Ahead
As mentioned earlier, this dish is nice to assemble in advance and then bake while you cook your main dish. Just follow the directions up until step 4, then place it in the fridge until dinner time. You may need to add a few minutes to the bake if it’s coming directly from the fridge, so look for the cheese to be melted and the bread to be toasted.
Looking for the Full Menu?
This casserole was designed as a side dish for my Romantic Winter Dinner Menu for Two. If you’re planning a cozy night in, check out the menu for more dinner inspiration!
