French Onion Soup Casserole is all about the comfort. French onion soup is already one of the great comfort foods of all time, the perfect savory dish to warm you from head to toe on a cold day. Now it’s in casserole form, so you can take slice after hearty slice of the caramelized sweet onions, the savory thick sauce, and the buttery French bread crust with melty cheese right on top. If that doesn’t scream warm and cozy, nothing does. French Onion Soup Casserole asks you for some patience to make it, but the final dish will make the effort all the sweeter! Now bundle up and dig in!
Ingredients
- 1 (16-ounce) baguette, cut into 1/4-inch slices
- 2 large Vidalia onions, halved and cut from top-to-bottom into 1/4-inch slices
- 3 large yellow onions, sliced
- 1/4 cup unsalted butter
- 1/2 teaspoon freshly ground black pepper
- 1 teaspoon kosher salt
- 1 bay leaf
- 5 fresh thyme sprigs, leaves removed, plus extra for topping
- 1/2 cup dry sherry
- 2 cups unsalted chicken broth
- 1 cup unsalted beef broth
- 8 ounces Gruyere cheese, shredded
Directions
Step 1 –Place an oven rack in the lower-middle position.
Step 2 –Preheat the oven to 400 degrees F.
Step 3 –Generously grease a 9×13-inch baking dish and the inside of a large Dutch oven with nonstick cooking spray.
Step 4 –Place the baguette slices onto a metal rack that’s resting on a baking sheet.
Step 5 –Bake the bread slices until golden brown, about 8-10 minutes.
Step 6 –Transfer the bread from the oven and set aside.
Step 7 –Add the sliced Vidalia onions, the sliced yellow onions, the butter, the black pepper, the salt, the bay leaf, and the thyme to the prepared Dutch oven.
Step 8 –Cover the Dutch oven tightly and cook in the oven for 1 hour.
Step 9 –Transfer the pot from the oven, then stir and scrape the bottom and sides of the pot.
Step 10 –Place the pot back into the oven with the lid slightly off and continue cooking until the onions are tender and slightly darker than golden-brown, about 1 hour-1 hour 30 minutes.
Step 11 –Transfer the pot to the stovetop over medium-high heat, stirring and scraping the sides and bottom. Use caution as the pot will be hot.
Step 12 –Remove and discard the bay leaf from the onions.
Step 13 –Add in the sherry, the chicken broth, and the beef broth.
Step 14 –Bring the mixture to a boil, stirring frequently, until slightly thickened, about 4-5 minutes.
Step 15 –Layer 1/2 of the baked baguette slices into the prepared casserole dish.
Step 16 –Spoon the onion mixture evenly over the bread.
Step 17 –Top the onion layer with the remaining bread slices.
Step 18 –Sprinkle the shredded cheese evenly over the top of the casserole.
Step 19 –Cover the casserole with foil and bake for 30 minutes.
Step 20 –Set the oven to broil and remove the foil.
Step 21 –Broil until the cheese is bubbly, about 3 minutes. Keep a close eye on it so it does not burn.
Step 22 –Garnish with extra thyme leaves and serve.
