5.0 from 12 votes
French Onion Casserole
A must-serve side dish or easy meatless dinner for all of your cozy gatherings this season!
Prep Time
10 mins
Cook Time
1 hr 10 mins
Total Time
1 hr 40 mins
Servings: 6 servings
Calories: 238 kcal
Course:
Side Dish , Main Course , Dinner
Cuisine:
American
Ingredients
- 3 medium sweet onions, sliced
- 3 tablespoons salted butter
- 4 cups beef broth (use vegetable broth or vegetable stock for a vegetarian dish)
- 1 teaspoon Worcestershire sauce
- 4 ounces French baguette bread, sliced about ½-inch in thickness (approximately 10-12 small slices)
- 1 cup (4 ounces) shredded mozzarella cheese (or sub with Gruyere or Fontina when available)
- ¼ cup grated Parmesan cheese
- Optional garnish: chopped fresh thyme or parsley
Instructions
- Preheat the oven to 350°F. Grease a medium casserole dish (approximately 2 quarts, or about 11 x 7-inches or 9-inches square). Set aside.
- Melt the butter in a large saucepan over low heat.
- Add the onions and cover. Cook for about 30 minutes, stirring occasionally.
- Add the beef broth and the Worcestershire sauce; bring to a boil.
- Reduce the heat to low. Allow the liquid to simmer, uncovered, for about 30 minutes so that the broth reduces.
- Pour the onion and broth mixture into the prepared baking dish.
- Lightly toast the slices of bread.
- Arrange the toasted bread in a single layer on top of onion and broth mixture.
- Cover the bread with a thick layer of shredded mozzarella. Sprinkle grated Parmesan over top.
- Bake, uncovered, for 20-30 minutes, or until cheese is melted and lightly browned on top. If you prefer a darker, crispier topping, you can place the dish under the broiler for the final 1-2 minutes (just keep a close eye on it so that it doesn't burn). Garnish with chopped fresh herbs, if desired.
Cup of Yum
Notes
- Want to Prep Ahead? Prepare the French onion soup base for the casserole (through Step 6) up to a day or two in advance. Keep it covered in the refrigerator until you're ready to bake it. Before baking, allow the dish to sit on the counter for at least 30-60 minutes so that it has time to come to room temp before you assemble and bake the casserole.
- I also like to toast the bread in advance. Allow the toast to cool completely and then just store it in a zip-top bag on the counter until you're ready to bake the casserole.
- Leftovers will keep in an airtight container in the fridge for 3-4 days; however, the bread will get soggy as it sits.
Nutrition Information
Serving
1/6 of the recipe
Calories
238kcal
(12%)
Carbohydrates
23g
(8%)
Protein
11g
(22%)
Fat
12g
(18%)
Saturated Fat
7g
(35%)
Polyunsaturated Fat
1g
Monounsaturated Fat
3g
Trans Fat
0.2g
Cholesterol
31mg
(10%)
Sodium
988mg
(41%)
Potassium
346mg
(10%)
Fiber
2g
(8%)
Sugar
10g
(20%)
Vitamin A
327IU
(7%)
Vitamin C
8mg
(9%)
Calcium
233mg
(23%)
Iron
1mg
(6%)
Nutrition Facts
Serving: 6servings
Amount Per Serving
Calories 238
% Daily Value*
| Serving | 1/6 of the recipe | |
| Calories | 238kcal | 12% |
| Carbohydrates | 23g | 8% |
| Protein | 11g | 22% |
| Fat | 12g | 18% |
| Saturated Fat | 7g | 35% |
| Polyunsaturated Fat | 1g | 6% |
| Monounsaturated Fat | 3g | 15% |
| Trans Fat | 0.2g | 10% |
| Cholesterol | 31mg | 10% |
| Sodium | 988mg | 41% |
| Potassium | 346mg | 7% |
| Fiber | 2g | 8% |
| Sugar | 10g | 20% |
| Vitamin A | 327IU | 7% |
| Vitamin C | 8mg | 9% |
| Calcium | 233mg | 23% |
| Iron | 1mg | 6% |
* Percent Daily Values are based on a 2,000 calorie diet.