French Onion Mac and Cheese

French onion soup and mac and cheese are two of the best comfort food dishes. Combining the two to make French onion Mac and cheese is the ultimate comfort food. Although this recipe has a few more steps than a classic mac and cheese dish, it is well worth it. I love to make this dish on the weekend as I have a little more time, and I appreciate the leftovers to start my week. If you have ever had the French onion macaroni and cheese from Trader Joe’s, this recipe is even better.

Why I love this French onion mac and cheese recipe

I love this recipe because it includes the best parts of French onion soup: rich caramelized onions, creamy and nutty gruyere cheese, and crunchy and gooey crouton.  These characteristics take the mac and cheese to the next level by making it cheesier, more flavorful, and extra comforting.  It is perfect on a cold day to warm and fill you up. (If you are like me and you just love cheesy recipes then I recommend trying my restaurant style queso recipe.)

I have seen some recipes where they make the cheese sauce in the same pot as the caramelized onions, the one from New York Times Cooking.  Although this saves a pot I find it easier to make the onions and cheese sauce separately and then bring them together before adding the pasta.  I find making a roux in a pot full of onions to be messy and the onions tend to clump on the whisk.

Ingredients in French onion mac and cheese

This recipe has a few more ingredients than many of my weeknight meals but these few additions really increase the flavor and make the mac and cheese extra delicious.  They help ensure you really get all that french onion soup flavor with the pasta.

• Sweet onions or Vidalia onions are best for this recipe but you can use yellow onions if there are what you have.  This recipe uses a lot of onions to really add all the caramelized onion flavor, but keep in mind they cook down a lot.
• Beef stock gives the recipe some extra flavor and helps it really have that French onion soup taste.  You can use vegetable or chicken stock instead.
• Red wine vinegar gives the dish a little acidity and helps bring out the flavor.
• Soy sauce is not something most people think to add soy sauce to their french onion soup, but a little bit helps really increase the rich, umami flavor of the onions and beef stock and reduces the amount of extra salt needed.  It is definitely my secret ingredient in french onion soup and french onion mac and cheese.
• Whole grain mustard gives a subtle tanginess to the recipe and does not overpower.  It can also be substituted for dijon mustard or omitted if you do not have any in your fridge.
• Macaroni pasta is my preference as I like the little elbow shaped noodles, however, you can use small shells, cavatappi or rotini if you prefer.
• Butter is used to cook the onions and make a roux that helps thicken the creamy cheese sauce.
• Flour is used with the butter to make a roux.
• Whole milk is the base of the cheese sauce and this dish is certainly saucy.
• Gruyere cheese gives that classic french onion soup flavor and is really noticeable when sprinkled on the baguette croutons on top.
• Cheddar cheese is used to help give it some extra cheesiness and also balances out the cost as gruyere can be expensive.
• Baguette is added to the top before baking to recreate that French onion soup crouton experience.

How to make French onion mac and cheese

As I said this recipe is slightly more involved than a traditional mac and cheese recipe.  It has the extra step of making the caramelized onions which give the dish that amazing french onion soup flavor.  This recipe is definitely worth the extra work!

Step 1: Grate the cheddar and gruyere cheese, setting aside 1 cup of gruyere.
Step 2: Slice the onions and saute them with butter and a pinch of salt  in a large skillet or pot over medium heat until golden brown.  You will need to stir the onions and scrape up any brown bits every few minutes to ensure they do not burn.  If the onions look dry you can add a little bit of the beef stock.  Once the onions are golden brown you will finish them in step 5.
Step 3: While the onions are cooking, preheat the oven to 450 degrees and cook the pasta in boiling water until 3 minutes shy of al dente and then strain.  The pasta will cook more in the oven in the cheese sauce.

• Step 4: Make the cheese sauce by melting the butter in a medium saucepan over medium heat and then adding the flour.  Allow to cook for about 2 minutes and then slowly add the milk while whisking. Once the milk has come to a simmer and thickened add in all the cheese except for the 1 cup of gruyere that you had set aside.  Once the cheese is melted into the sauce, turn off the heat.
• Step 5: The onions should be mostly done and a deep golden brown.  Add the red wine vinegar to deglaze the pan and scrape up any remaining bits on the bottom.  Then add the soy sauce, beef broth and mustard and allow to simmer until the liquid has reduced by half.
• Step 6: Mix the cheese sauce in with the onions and fully combine. Then add in the cooked pasta.
• Step 7: Transfer the pasta in sauce to a large greased baking or casserole dish and top with the sliced baguette and remaining cup of shredded gruyere cheese.
• Step 8: Bake for 15 minutes until the baguette is toasted and the cheese is bubbling and browned in spots.
• Step 9: Remove the french onion mac and cheese from the oven and allow to rest before serving.

Ingredient substitutions and omissions

• Beef broth or stock can be substituted with chicken or vegetable or omitted.  If you omit you may need to add a little water to the onions if they seem dry
• Gruyere cheese can be substituted with American Swiss, Fontina, Comte, Jarlsberg or Gouda.  Some of these alternatives can also be much less expensive.
• Soy sauce can be left out but I think it really improves the dish.  If you remove it you will need to add a teaspoon of salt to the onions at the end.
• Whole grain mustard can be substituted with dijon mustard or omitted if you do not want that subtle mustard zip.
• Red wine vinegar can be substituted for white wine vinegar, balsamic vinegar or sherry vinegar

French Onion Mac and Cheese

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A delicious combination of French onion soup flavors and mac and cheese.  The perfect comfort food dinner.

• Total Time: 45 mins
• Yield: 6 servings 1x

Ingredients

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• 2 pounds sweet onions (Vidalia) or yellow onions, peeled, halved and thinly sliced
• 6 tablespoons of butter, plus more for greasing the pan
• Kosher salt
• 3 tablespoons red wine vinegar
• 2 tablespoons soy sauce
• 1 tablespoon whole grain mustard
• 1 cup of beef broth
• 1 pound of elbow pasta or alternative
• 4 tablespoons of flour
• 3 cups whole milk – you can add 1 cup more if you want a saucier or looser mac and cheese
• 1 pound white cheddar cheese, grated (about 5 cups)
• 12 ounces gruyere cheese, grated (about 4 cups)

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Instructions

1. Grate the cheddar and gruyere cheese, setting aside 1 cup of gruyere.
2. Cut the onions in half, peel them and then thinly slice them.   
3. In a large pot or sauce pan melt 2 tablespoons of butter over medium heat. Add the onions and ½ teaspoon of salt and saute until golden brown, about 20 minutes.  You will need to stir the onions and scrape up any brown bits every few minutes to ensure they do not burn.  If the onions look dry you can add a few tablespoons of beef stock. Once the onions are golden brown you will finish them with step 7.  If you are note ready to finish them simply turn off the heat until you are ready to resume.
4. While the onions are cooking, preheat the oven to 450 degrees
5. Cook the pasta in boiling water until 3 minutes shy of al dente (as listed on the package) and then strain.  The pasta will cook more in the oven in the cheese sauce which is why you want to undercook it.
6. Make the cheese sauce by melting the butter in a medium saucepan over medium heat.  Add the flour and let it cook for about 2 minutes.  Slowly add the milk while whisking. Once the milk has come to a simmer and thickened add in all the cheese except for the 1 cup of gruyere that you had set aside.  Once the cheese is melted into the sauce, turn off the heat.
7. The onions should be mostly done and a deep golden brown by now.  Add the red wine vinegar to deglaze the pan and scrape up any remaining bits on the bottom.  Then add the soy sauce, beef broth and mustard and allow to simmer until the liquid has reduced by half.  Turn off the heat.
8. Mix the cheese sauce in with the onions and fully combine. Then add in the cooked pasta.
9. Transfer the pasta in sauce to a large greased baking or casserole dish and top with the sliced baguette and remaining cup of shredded gruyere cheese.
10. Place the baking dish on a sheet pan and bake for 15 minutes until the baguette is toasted and the cheese is bubbling and browned in spots.
11. Remove the french onion mac and cheese from the oven and allow to rest for 15 minutes before serving.
    
    

Notes

Total Recipe Cost: $25 or $4.16 per serving

• Author: Anthony Vipond
• Prep Time: 5 mins
• Cook Time: 40 mins
• Category: Pasta, Comfort Food
• Method: Oven, Stovetop
• Cuisine: American

Keywords: French onion soup, mac and cheese, pasta, comfort food