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French Onion Soup Mac and Cheese
Flona

French Onion Soup Mac and Cheese

French Onion Soup Mac and Cheese combines the best of two comfort food classics into one irresistible dish. Deeply caramelized onions mingle with a rich, creamy three-cheese sauce coating tender pasta, all topped with golden, crispy breadcrumbs. The result is a decadent casserole that captures the essence of French onion soup in creamy, satisfying form.
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Prep Time 15 minutes
Cook Time 45 minutes
Onion Caramelization Time 30 minutes
Total Time 1 hour
Servings: 6 servings
Course: Dinner
Cuisine: American
Calories: 520
Ingredients Equipment Method Notes

Ingredients
  

For the Pasta and Onions
  • 12 oz elbow macaroni or shells, cavatappi
  • 3 large yellow onions thinly sliced
  • 2 tbsp olive oil
  • 3 tbsp butter divided
  • 2 cloves garlic minced
  • 1 tsp fresh thyme or 1/2 tsp dried
For the Cheese Sauce
  • 3 tbsp all-purpose flour
  • 2 cups vegetable broth
  • 2 cups whole milk
  • 0.5 cup heavy cream
  • 2 cups Gruyère cheese shredded
  • 1 cup sharp cheddar cheese shredded
  • 1 cup mozzarella cheese shredded
  • 1 tsp salt
  • 0.5 tsp black pepper
For the Topping
  • 1 cup breadcrumbs or panko
  • 0.5 cup Parmesan cheese grated

Equipment

  • Large skillet
  • Large pot for pasta
  • Whisk
  • Baking dish or oven-safe skillet
  • Mixing bowl

Method
 

  1. Preheat oven to 375°F (190°C). Butter a large baking dish or have an oven-safe skillet ready.
  2. Heat olive oil and 1 tablespoon butter in a large skillet over medium heat. Add sliced onions and cook, stirring often, for 25-30 minutes until deeply caramelized and golden brown. Stir in garlic and thyme, cooking 1 minute more.
  3. Add remaining 2 tablespoons butter to the caramelized onions. Once melted, stir in flour and cook for 2 minutes, stirring constantly to form a roux.
  4. Slowly whisk in vegetable broth until smooth, then add milk and cream. Bring to a gentle simmer and cook for 5 minutes until thickened. Remove from heat and stir in Gruyère, cheddar, and mozzarella until melted. Season with salt and pepper.
  5. Cook pasta in salted boiling water until just al dente (1-2 minutes less than package directions). Drain well. Add pasta to cheese sauce and fold gently to coat. Transfer to prepared baking dish if not using oven-safe skillet.
  6. Mix breadcrumbs with Parmesan and sprinkle evenly over the top. Bake for 20-25 minutes until bubbling and golden brown. Let rest 5 minutes before serving.

Notes

Patience with caramelizing the onions is key - don't rush this step. Cook pasta slightly underdone as it continues cooking in the oven. For best melting, shred cheese from a block rather than using pre-shredded. Can be assembled a day ahead; add topping right before baking. Freezes well unbaked for up to 3 months.