Go Back
–+ servings
French Onion Broccoli Cheese Casserole

Heavenly French Onion Broccoli Cheese Casserole Recipe

This French Onion Broccoli Cheese Casserole is a cozy vegetarian dish featuring caramelized onions, creamy cheeses, and a crispy topping.
Print Recipe Pin Recipe
Prep Time 30 minutes
Cook Time 22 minutes
Resting Time 10 minutes
Total Time 1 hour 2 minutes
Servings: 6 servings
Course: Dinner
Cuisine: French
Calories: 350
Ingredients Equipment Method Nutrition Notes

Ingredients
  

For the Casserole
  • 2 tablespoons Olive oil Can substitute with canola or vegetable oil.
  • 2 tablespoons Unsalted butter Can use salted butter with reduced salt.
  • 3 medium Yellow onions Sweet onions can be used for a gentler taste.
  • 1 tablespoon Granulated sugar Enhances sweetness of the caramelized onions.
  • 1 teaspoon Kosher salt Balances flavors.
  • 3 cloves Garlic Use fresh minced garlic for the best flavor.
  • 1 teaspoon Dried thyme Can swap with oregano or Italian seasoning.
  • 4 tablespoons All-purpose flour Thickens the cheese sauce.
  • 2 cups Low-sodium beef broth For vegetarian option, use vegetable broth.
  • 1 cup Whole milk Substitute with heavy cream or plant-based milk.
  • 4 cups Broccoli florets Can use thawed frozen broccoli.
  • 1 cup Gruyère cheese Swiss or Jarlsberg can serve as substitutes.
  • 1 cup Sharp cheddar cheese Used in sauce and as topping.
  • 1 teaspoon Ground black pepper Enhances overall flavors.
For the Topping
  • 1 cup Panko breadcrumbs French-fried onions can be a flavorful alternative.
  • 2 tablespoons Unsalted butter Used to crisp the topping.
  • 2 tablespoons Fresh parsley Optional garnish.

Equipment

  • large skillet
  • medium saucepan
  • Baking Dish
  • colander

Method
 

Step‑by‑Step Instructions
  1. Preheat your oven to 375°F (190°C) and grease a 9×13-inch baking dish with olive oil or butter.
  2. In a large skillet, heat olive oil and unsalted butter. Add the sliced onions with kosher salt and sugar. Caramelize for 20-25 minutes, adding garlic and thyme in the last minute.
  3. Blanch the broccoli florets in boiling water for 2 minutes. Drain and pat dry with a towel.
  4. In a saucepan, melt unsalted butter and whisk in flour. Gradually add beef broth and milk, stirring until thickened. Mix in Gruyère and half the cheddar.
  5. Combine blanched broccoli and caramelized onions in the baking dish. Pour the cheese sauce over and stir to coat. Top with remaining cheddar.
  6. Mix panko breadcrumbs with melted butter. Add parsley if desired. Spread the mixture over the casserole.
  7. Bake for 18-22 minutes until bubbly and golden brown. Let rest for 5-10 minutes before serving.

Nutrition

Serving: 1servingCalories: 350kcalCarbohydrates: 30gProtein: 12gFat: 22gSaturated Fat: 10gPolyunsaturated Fat: 2gMonounsaturated Fat: 8gCholesterol: 50mgSodium: 800mgPotassium: 400mgFiber: 3gSugar: 4gVitamin A: 20IUVitamin C: 50mgCalcium: 25mgIron: 10mg

Notes

Using high-quality ingredients will elevate the dish's flavor and cheesiness. Watch the topping closely while baking to prevent burning.

Tried this recipe?

Let us know how it was!