French Onion Chicken Casserole

All the flavor of a classic bowl of French onion soup, turned into a hearty casserole with shredded chicken, sweet caramelized onions, and a crusty baguette and Gruyere topping. It comes together in one skillet with about 10 minutes of hands-on work!

Course Dinner

Cuisine American

Keyword french onion baked chicken, french onion chicken bake, french onion chicken casserole

Prep Time 10

Cook Time 30

Total Time 40

Servings people

Calories 379kcal

Author Blair Lonergan

Equipment

Ingredients

2 tablespoons salted butter
1 lb. Vidalia onions, or other sweet onions, thinly sliced (about 2 medium onions)
Kosher salt and ground black pepper, to taste
1 teaspoon minced fresh thyme leaves (or about ¼ teaspoon dried thyme)
1 clove garlic, peeled and minced or pressed
1 tablespoon balsamic vinegar
1 teaspoon Worcestershire sauce
3 cups cooked, diced or shredded chicken (such as the meat from a rotisserie chicken)
1 cup chicken stock or beef broth
9 to 10 slices crusty French baguette (or other similar bread), sliced about ½-inch thick
1 cup grated Gruyere cheese (or sub with grated Swiss cheese)
Optional, for serving: chopped fresh thyme or parsley for garnish

Instructions

Toast the bread: Preheat oven to 475°F. Arrange the bread slices on a baking sheet and toast lightly, about 4 to 5 minutes. Set aside.
Soften the onions: Melt the butter in a medium ovenproof skillet over medium-high heat. Add the onions and season with salt and pepper. Cover with a lid and cook, stirring occasionally, until softened, about 3 to 5 minutes.
Caramelize: Remove the lid, stir in the thyme and garlic, and continue cooking and stirring until the onions are deep golden brown, about 15 minutes. As they cook, add a tablespoon of water and stir. Once it evaporates, repeat with additional tablespoons of water. This keeps the onions from burning and speeds up caramelization.
Add the vinegar: Stir in the balsamic vinegar and Worcestershire sauce and cook for 1 more minute.
Add chicken and broth: Stir in the chicken and broth, scraping up any browned bits from the bottom of the pan. Taste and season with salt and pepper. Bring to a boil, then remove from the heat.
Top it: Arrange the toasted bread slices over the chicken and onion mixture in a single layer, then sprinkle the cheese over the top.
Bake: Place the skillet in the 475°F oven for 5-10 minutes, until the cheese melts and starts to brown.
Serve: Garnish with chopped fresh parsley or thyme, if desired, and serve right away.

Video

Notes

Pan: I use this 2.25-quart Le Creuset braiser, an oven-safe skillet with a lid. A 9-inch or 10-inch cast iron skillet also works well. No oven-safe skillet? Transfer the filling to a 2-quart baking dish before topping.
Chicken: Use rotisserie, boiled and pulled, leftover, or canned chicken. You'll need about 3 cups.
Cheese: Comté is the most traditional choice, Gruyère is the easy stand-in, and Swiss, provolone, mozzarella, or Gouda all melt well. Grate it yourself rather than buying pre-shredded.
Broth: Beef broth gives a deeper, more traditional flavor and chicken broth keeps it lighter. Both work.
Storage: Leftovers keep in an airtight container in the refrigerator for 3 to 4 days. The bread softens as it sits, so this is best the day it's made.
Freezing: Freeze the chicken and onion filling on its own for up to 3 months, without the bread and cheese. Thaw, warm on the stovetop, then top with fresh bread and cheese and bake.
Reheating: Cover loosely with foil and bake at 350°F for 15 to 20 minutes, or microwave individual portions for 1 to 2 minutes.

Nutrition