French Onion Grilled Cheese

Can’t decide between French Onion Soup or Grilled Cheese?  Try this yummy French Onion Grilled Cheese that will satisfy your craving for both.

French Onion Grilled Cheese |

This sandwich.

I can’t even begin to describe how delicious this is. 

If you are a lover of French Onion Soup, or just love soft and sweet caramelized onion, you have to try this incredible grilled cheese. 

I love creating fun and tasty sandwiches and burgers.  They are on my dinner menu a few nights a week.  From BLT’s, to a classic Grilled Cheese sandwich paired with my quick and easy homemade Creamy Tomato Soup, you can’t beat a soup and sandwich dinner night.  To save a step, you can cook the onions ahead time and have the ready to go in your refrigerator.

Not only is this grilled cheese great for a dinner, but I love the idea of making them for parties.  You can cut them in half and serve on a platter or even cut them smaller for mini sandwiches.  Great for your game day buffet along with a pot of chili. 

What I love about this French Onion Grilled Cheese is the kickin’ sauce I created that combines worcestershire sauce, mayonnaise, garlic powder, parsley and thyme.  Combined with the creamy cheese and a few slices of sourdough bread,  this sauce adds the finishing touch to this tasty grilled cheese sandwich. 

French Onion Grilled Cheese |

What you need
Yellow onions
Olive oil
Balsamic vinegar
Worcestershire sauce
Garlic powder
Parsley flakes
Dried thyme
Deli swiss or provolone cheese
Sourdough bread

Heat olive oil in a large skillet over medium heat. Add sliced onion, season with salt and cook, stirring occasionally for about 18-20 minutes until tender and golden brown. Stir in balsamic vinegar and cook for 1-2 minutes longer.

French Onion Grilled Cheese |

French Onion Grilled Cheese |

Butter outside of bread. In a small bowl mix mayonnaise, worcestershire sauce, garlic powder, parsley and thyme. Spread on both slices of bread. Top with cheese and onions. Top with remaining slice of bread. Toast each side of bread in a large skillet until cheese is melted. I like to use the same skillet that the onions were cooked in to infuse the flavor from the pan into the bread.

French Onion Grilled Cheese |

French Onion Grilled Cheese |

French Onion Grilled Cheese |

French Onion Grilled Cheese |


French Onion Grilled Cheese

  • Prep Time: 15 minutes
  • Cook Time: 30 minutes
  • Total Time: 45 minutes
  • Yield: 4 servings


Caramelized Onions

  • 1 pound yellow onions, sliced
  • 3 tablespoon olive oil
  • 1/4 teaspoon salt
  • 1 teaspoon balsamic vinegar


  • 1/2 cup mayonnaise, regular or light
  • 3 teaspoons worcestershire sauce
  • 1 teaspoon garlic powder
  • 1/2 teaspoon parsley flakes
  • Pinch of dried thyme

Grilled Cheese

  • 8 slices deli sliced swiss or provolone cheese
  • 8 slices bakery fresh sourdough bread
  • 12 tablespoons butter


Prepare onions

  1. In a large skillet heat olive oil over medium heat.
  2. Add onions, season with salt and stir to coat with olive oil.
  3. Cook onions over medium heat, stirring occasionally to avoid burning until onions are brown and caramelized, about 20 minutes.
  4. Stir in balsamic vinegar and cook for about 2 minutes.
  5. Remove from heat and set aside.

Prepare spread

  1. In a medium bowl stir mayonnaise, worcestershire sauce, garlic powder, parsley flakes and thyme until combined. Store in the refrigerator until ready to serve.

Prepare grilled cheese

  1. Heat a large skillet over medium heat.
  2. Butter outside pieces of bread.
  3. Inside the sandwich, spread both slices with mayonnaise spread. Top with 2 slices of cheese and caramelized onions.
  4. Cook sandwich about 4-5 minutes per side until bread is toasted and golden brown and cheese is melted.

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