Gruyere Grilled Cheese with Caramelized Onions & Mustard

For a quick and easy dinner, try this dish. The caramelized onions will give it an extra depth of flavor that is totally worth the prep time.

Gruyere is a type of Swiss cheese that pairs well with caramelized onions. It also has a distinctive nutty flavor and a smooth, creamy texture.


It’s National Grilled Cheese Day today. What a wonderful holiday, huh? National Grilled Cheese Day, in my opinion, should be declared a national holiday. Marching bands may be heard marching along Main Street. “HAVE A GOUDA DAY,” say Girl Scouts brandishing enormous felt banners. People walking about with walrus tusks stuck in their mouths.

Moms and dads are competing in a homemade grilled cheese competition to see who can make the best golden crisp. Dairy-free individuals sobbing as they eat soy grilled cheese since they can’t have the genuine thing. People are adopting them nevertheless since cheese is so popular.

But, if I may, I’d like to make a wild suggestion. In this Gruyere grilled cheese, who’s the star? It isn’t the cheese, however. It’s because of the mustard. Specifically, Maille’s old style whole grain mustard. It elevates this Gruyere grilled cheese sandwich to the next level. This grilled cheese becomes the ultimate of quality and simplicity when Maille is added. It complements the soft gruyere well, and its subtle acidity cuts through the sweetness of the caramelized onions.

I’ll let you in on a little secret: it’s something amazing.


What kind of bread is ideal for grilled cheese sandwiches?

In my view, the only bread you should use to create homemade grilled cheese sandwiches is a fresh loaf of sourdough. Sourdough has a subtle tanginess to it that complements any cheese well. In addition, sourdough is quite durable and does not toast too quickly in the pan. When used for grilled cheese sandwiches, I appreciate how sourdough becomes somewhat crusty crunchy on the exterior while remaining rather fluffy on the interior. 

Please wait a moment. My keyboard was splattered with drool. 


How to create the ideal grilled cheese sandwich

Making the ideal grilled cheese sandwich is a fine art form, believe it or not. People often overheat the bread, use the incorrect kind of cheese, or do something else as awful. Here’s how I always make the best Gruyere grilled cheese: 

Use mayo instead of butter on the exterior of the bread – I know it seems funny, but using mayo instead of butter on the outside of the bread is a game changer. Because mayonnaise is simpler to spread, you’ll need less of it. As a result, the sourdough may crisp up without becoming oily. 

Use grated cheese instead of sliced cheese since grated cheese melts better. Granted, piling the cheese on top of the sandwich this manner is a bit more difficult, but it’s well worth it in the end. 

Add a dash of mustard – Whether you’re cooking this Gruyere grilled cheese or another grilled cheese, a dash of mustard helps cut through the creamy cheese and crunchy bread. 

Maintain a medium heat in the pan — Making a Gruyere grilled cheese is a bit of a Goldilocks moment. The bread will not crisp up on the exterior if the heat is too low; yet, if the heat is too high, the bread will burn and the cheese will not have time to melt. Maintain a medium heat setting for the best results. 


Now that National Grilled Cheese Day has here, it’s time to treat yourself with something special. Let’s hear it for the cheese!


Grilled Cheese with Caramelized Onions, Whole Grain Mustard, and Gruyere that’s wonderful for spring. Take a look at that stunning cheese pull!


To prepare the caramelized onions (enough for 3 grilled cheese sandwiches):

  • 4 big white or yellow onions, halved and thinly sliced
  • 1 tablespoon olive oil plus 1/4 cup
  • 1 cup of water
  • salt (1/4 teaspoon)

To make the grilled cheese, combine the following ingredients in a large mixing bowl.

  • 2 slices sourdough bread, fresh
  • mayonnaise, 1 tablespoon
  • 2 ounces grated gruyere cheese
  • a quarter-cup Whole Grain Maille Maille Maille Maille Maille Maille Maille Maille Maille Mustard Dijon
  • 3 tablespoons caramelized onions (from the previous recipe)
  • a few fresh thyme sprigs


  1. Over medium heat, heat a heavy-bottomed saucepan. Add the onions and 1 tablespoon of olive oil to the pan. Cook for 1 minute, or until well heated, then reduce heat to low and add 1/4 cup water, the remaining 1/4 cup olive oil, and salt.
  2. Cook for 1 hour, stirring periodically. The onions will change color from white to transparent until becoming golden brown. If the onions seem to be dry, add 1-2 teaspoons more water as needed.
  3. Remove the onions from the fire after they’ve attained a good medium golden brown color and set aside to cool somewhat. In the refrigerator, onions may be kept for up to a week.
  4. Heat a pan over medium heat for the grilled cheese. Mayonnaise should be smeared on both slices of sourdough, then Maille Old Style Whole Grain Dijon Mustard should be spread over the other side of one of the pieces. Place both slices on the griddle, mayo side down.
  5. Spread the caramelized onions over the mustard piece of bread and top with a few fresh thyme leaves. Place the grated gruyere on top of the other slice with care. Cook for another 2-3 minutes, or until the cheese has fully melted.
  6. Sandwiches should be pressed together and sliced on the diagonal before serving.

More simple lunch dishes may be found at: 

Sandwich of green falafel with beet hummus

Asian BBQ Pulled Chicken Sandwiches in the Slow Cooker

Spaghetti with White Wine and Cream Sauce of Roasted Tomatoes

Ottolenghi’s Fattoush Salad reimagined

Creamy Chicken Corn Chowder with a Twist


Maille is the sponsor of this content. Thank you for your continued support of the brands that enable Broma to exist!

Grilled cheese with caramelized onions and bacon is a classic combination. The Gruyere Grilled Cheese with Caramelized Onions & Mustard is a quick and easy dish that can be made in just minutes. Reference: grilled cheese with caramelized onions and bacon.

Frequently Asked Questions

What compliments caramelized onions?

A: Its hard to say definitively, but caramelized onions are usually characterized by sweet and savory notes. Theyre often paired with garlic or thyme in a dish that requires some type of browning.

What type of cheese is best for grilled cheese?

A: Manchego is the best type of cheese for grilled cheese.

Can you caramelize cheese?

A: Yes, you can.

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