The Ultimate French Onion Soup Grilled Cheese

Recipe courtesy of

Prep time: 5 minutes
Cook time: 45 minutes
Total time: About 50 minutes

Servings: 2 sandwiches (2 biiiig, honking sandwiches)

1 large yellow onion
2 Tbsp butter
2 Tbsp red wine or beef broth
4 pieces good sandwich bread
2 Tbsp mayo
½ lb gruyere cheese, sliced thinly

*Note: I got my gruyere and unreal sourdough sandwich from Whole Foods Market. You should too.


  1. Place a skillet over medium-low heat, add 1 tablespoon butter and then add in the onions once the butter is totally melted.
  2. Stir the onions every 5-10 minutes. They’ll become a deep golden brown and all of their natural sugars will release. This will take patience! Perfect caramelization should take around 30-35 minutes.
  3. When your onions are a deep brown and fully caramelized, add the red wine or broth to deglaze the pan, being sure to scrape off all the brown bits from the bottom that might be stuck. Season with salt and let cool to warm.
  4. Slather one side of each piece of bread with mayo (these will be your outside pieces).
  5. Place a huge heaping spoonful of your onions and hefty slices of gruyere onto one piece of bread (the un-mayoed side). Top with the other piece of bread.
  6. Melt remaining tablespoon of butter in a skillet over medium heat. Make sure the pan is very hot, and then place your sandwich on one side and put something heavy, like a pot, on top to weigh it down. 
  7. Flip the sandwich, brown the other side, and wait until cheese is melted.
  8. Cry about how perfectly glorious and golden this sandwich is.