Fantastic recipe! Saw a neighbor bring this to a block party, and everyone went bonkers for it!

This French Onion Soup Casserole takes the deeply savory, cheesy, and comforting flavors of the classic French soup and transforms them into a hearty, easy-to-serve baked casserole. It features layers of caramelized onions, rich broth, toasted bread, and a blanket of melted Gruyère and Parmesan cheese.

French Onion Soup Casserole

Ingredients:

How To Make French Onion Soup Casserole:

1. Step 1: Prep and Preheat: Preheat your oven to 400°F (200°C) and prepare a 9×13 inch baking dish with cooking spray.
2. Step 2: Caramelize the Onions: In a large pan or Dutch oven over medium heat, melt the butter. Add the thinly sliced sweet onions and caramelize them until they are soft, sweet, and golden brown. This should take about 15 minutes; stir occasionally for even browning.
3. Step 3: Build the Base: Add the minced garlic, salt, pepper, and thyme to the onions and cook for another minute until fragrant.
4. Step 4: Create the Roux and Deglaze: Sprinkle the flour over the onions and cook for a couple of minutes, stirring constantly. Then, pour in the dry white wine and simmer, scraping up any browned bits, until the liquid reduces slightly.
5. Step 5: Simmer the Broth: Add both the beef broth and chicken broth to the pan and bring everything to a simmer. Let it simmer for another 10 minutes, allowing the flavors to meld and deepen.
6. Step 6: Assemble the Casserole: Pour half of the onion mixture into the prepared baking dish. Layer half of the toasted bread slices on top, then sprinkle with half of the Gruyère and Parmesan cheeses. Repeat these layers with the remaining ingredients.
7. Step 7: Bake and Finish: Bake the casserole uncovered for 20-25 minutes, or until the cheese is bubbly and beautifully browned on the edges. Let the casserole sit for a few minutes before serving to allow it to set. Garnish with fresh chopped parsley and enjoy!