French Onion Mac and Cheese

4.88 from 25 votes

French Onion Mac and Cheese

This French Onion Mac and Cheese is made with deeply caramelized onions, Gruyère, and a creamy cheese sauce, then broiled until golden and bubbly. A rich, cozy, and indulgent twist on classic French onion soup.

Prep Time20

Cook Time1

Total Time1 20

Course: Main Course

Cuisine: American

Keyword: Cheese, Holiday, Onions, Pasta, Winter

Servings:

Author: Carolyn Stilwell

Equipment

Chef Knife
Dutch Oven or large heavy bottom pot
Pot
Box Grater
Oven Safe Crocks or use a baking dish

Ingredients

Caramelized Onions

1 tablespoon Extra Virgin Olive Oil
1 tablespoon Butter
3 Yellow Onion thinly sliced (use 2 onions if large)
1 pinch Kosher Salt
3 sprigs Fresh Thyme
¼ cup Sherry
1 teaspoon Worcestershire Sauce

Mac and Cheese

8 ounces Pasta I used shells
4 tablespoons Butter
¼ cup All Purpose Flour
1 ½ cups Whole Milk
¼ teaspoon Dry Mustard
½ teaspoon Cayenne
¼ teaspoon Smoked Paprika
½ teaspoon Garlic Powder
½ teaspoon Black Pepper
1 teaspoon Better Than Bouillon Reduced Sodium Beef Base optional (add extra salt if omitting)
1 cup Cheddar Cheese shredded (I used Trader Joe's Caramelized Onion Cheddar Cheese)
1 cup Gruyère Cheese shredded

Topping

2 tablespoons Butter melted
1 cup Panko Breadcrumbs
⅛ teaspoon Cayenne
¼ teaspoon Smoked Paprika
¼ teaspoon Garlic Powder
Kosher Salt & Black Pepper to taste
¼ cup Cheddar Cheese shredded
¼ cup Gruyère Cheese shredded
¼ cup Parmesan Cheese grated

US Customary - Metric

Instructions

Caramelized Onions

Start the onions: Heat olive oil and butter in a Dutch oven or large pot over medium heat. Add the onions and a big pinch of salt. Stir, cover, and cook for 5 minutes.
Caramelize: Reduce heat to medium-low and cook uncovered for 30 to 40 minutes, stirring occasionally, until deeply golden. Add thyme sprigs halfway through.
Deglaze: Add the sherry and scrape up any browned bits. Stir in Worcestershire sauce and cook until the liquid reduces. Remove and discard the thyme sprigs.

Mac and Cheese

Cook the pasta: While the onions caramelize, boil the pasta 1 minute less than package directions. Drain and reserve ½ cup of pasta water.
Make the roux: In a saucepan, melt the butter over medium heat. Whisk in the flour and cook for 2 minutes until lightly golden. Slowly whisk in the milk. Add dry mustard, cayenne, smoked paprika, garlic powder, black pepper, and beef base (if using). Increase heat to medium-high and whisk constantly for 3 to 5 minutes until thickened.
Add the cheese: Remove from heat and stir in the cheddar and Gruyère until melted and smooth.
Combine: Stir the cooked pasta into the cheese sauce. Add a splash of pasta water if the sauce needs thinning. Fold in the caramelized onions.

Topping and Assembly

Make the topping: Preheat broiler. Mix the melted butter with panko, cayenne, smoked paprika, garlic powder, salt, and pepper.
Assemble: Spoon the mac and cheese into oven-safe crocks or a baking dish. Add the breadcrumb topping, then extra cheddar, Gruyère, and Parmesan. Finish with cracked pepper.
Broil: Broil for 3 to 5 minutes, watching closely, until golden and bubbly. Serve hot.

Video

Notes

Caramelizing the onions: Take your time with this step for the best French onion flavor. Cook the onions low and slow until deep golden brown, stirring occasionally.
Cheese: For the creamiest sauce, use freshly shredded cheddar and Gruyère. Pre-shredded cheese can make the sauce grainy. Add the cheese off the heat and stir until fully melted.
Pasta: I used pasta shells because they hold onto the sauce well. Cavatappi, elbow macaroni, or rotini also work.
Bakeware: If you don’t have oven-safe crocks, bake in a 2–3 quart baking dish (such as a casserole dish or 9×13 pan).
Broiling: Broil for 3-5 minutes, watching closely. The topping can brown quickly.
Make Ahead: Assemble up to 1 day ahead (without the panko topping), cover tightly, and refrigerate. Add the topping just before broiling so it stays crisp.
Storage: Store leftovers in an airtight container in the fridge for up to 4 days.
Reheat: Reheat in the oven at 350°F until warmed through, or microwave in short bursts. Add a sprinkle of extra cheese or breadcrumbs before reheating if you want to refresh the topping.

Nutrition