Balsamic Caramelized Onion Grilled Cheese Sandwich

When I was younger, my hobbies included collecting Sanrio Keroppi paraphernalia, making choreographed dance videos to every Disney princess movie, working out different design concepts for my dollhouse, journaling, collecting rocks/geodes, and of course the standard eldest sister hobby of tattling on my brothers.

This wasn’t the standard, “Maaaaaaahhhhmmmm!!!! Zack kicked me!” Even though, I am not going to lie, I did that a time or two or thirty seven as well.

My style of tattling was only when I knew that they were going to end up in big, big trouble if my Mom or Dad did not intervene. I was really just doing them a favor…plus there was a nice little vindication that came along with it and then moved the spotlight off of me for a few days.

One particular incident will always live in infamy in our house. I got wind through my brother’s incessant bragging that he and his chums had stolen some lawn reflectors from a friend’s yard. They got away with it, for the time being, so they started to get a bit cocky.

They then moved on to driving through the downtown area of our hometown, launching water balloons at innocent bystanders walking through the city. Yep, that’s my brother. Which one you ask? I’ll never teeeelllll!

After telling my Mom, the diabolical mastermind that she is, she jumped into action. As soon as my brother came home from school, she had the local paper’s crime report open on the kitchen table. She started to tell him about some unsolved crime in the area which just happened to sound a lot like what he and his pals had been doing. The color drained from his face.

The next day, he and his friends went and returned all the reflectors to the proper lawns. He thought he was in the clear until I told him that Mom knew the whole time and that he had been outsmarted. But he never did anything like that again. Or maybe he just never told me again!

What this has to do with grilled cheese, you ask? Well, grilling up some cheese and bread was another one of my childhood hobbies. It may in fact still be a favorite hobby of mine. I think today I have adultified the grilled cheese of my youth by adding a fancy cheese and some slightly sweet balsamic onions. Done and done!

Balsamic Caramelized Onion Grilled Cheese Sandwich

Course Sandwich
Prep Time 5 minutes
Cook Time 25 minutes
Total Time 30 minutes
Author Sarcastic Cooking


  • 1 Yellow Onion skin removed, halved and then sliced
  • 3 Tablespoons Unsalted Butter
  • 1 Tablespoon Olive Oil
  • 2 Tablespoons Balsamic Vinegar
  • Pinch Salt & Pepper
  • 1 Tablespoon Fresh Chopped Basil
  • 2 Cups Shredded Fontina Cheese
  • 4 Slices of Bread
  • 3-4 Tablespoons Unsalted Butter for the bread


  1. Add butter and olive oil to a large skillet, heat for a minute over medium/high heat until the butter melts. Add the onions. Stir and cook the onions until they become translucent and slightly browned on the edges, about seven minutes. Add the balsamic vinegar, salt, and pepper. Sautee onions until deeply caramelized, about another ten to twelve minutes. Once caramelized, add chopped basil and turn off heat.
  2. Warm a large skillet or griddle for two minutes over medium heat.
  3. Butter one side of each slice of bread. Place the bread butter side down on the griddle, top each slice with about a half a cup of shredded cheese. Place half the caramelized onions on two slices of bread. After about three to four minutes flip the slice with only the cheese on to the top of the slice with the onions. Cook another minute or two until golden and melty.
  4. Let sandwich sit for a minute or two before cutting or serving so the cheese has time to slightly harden. Serve immediately.

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  • Ian schafer
    August 18, 2013 at 1:12 am

    I do a version of this just add bacon & add grated Romano, Pecorino or Parmesan cheese to the buttered side of the sandwich before grilling … YUMMO !!!

  • Renae
    January 30, 2013 at 12:02 am

    Just wanted to let you know that I tried this recipe over the weekend. Delish!!! Thanks for posting!

  • Anita at Hungry Couple
    January 26, 2013 at 11:07 am

    I am an only child so I never got to tattle on anybody. Brian, however is the oldest of 3 and the youngest is a sister that loved tattling on him and his brother. I’m not sure he’s forgiven her yet. 🙂 As for this grilled cheese, I didn’t even know how badly I wanted caramelized onions on my grilled cheese until I saw this!!

  • M
    January 25, 2013 at 8:17 am

    I LOVE grilled cheese(or really, cheese in general). It is a pretty common fallback meal for my husband and me, since we NEVER run out of cheese or bread. I made my own facy grilled cheese a few weeks ago, spinach and artichoke grilled cheese, I’m seeing carmelized onion grilled cheese in my near future!

  • Stephie @ Eat Your Heart Out
    January 24, 2013 at 8:25 pm

    Sometimes you make me even more glad I don’t have siblings. 😛

    Feed me this sandwich.

  • Julia
    January 24, 2013 at 8:02 pm

    I love grilled cheese! I can eat it plain every day but with these caramelized onions–EVEN BETTER! Looks delicious.

  • Ashley Bee (Quarter Life Crisis Cuisine)
    January 24, 2013 at 2:52 pm

    Caramelized onions will always look like worms. But these do look delicious!

    • Stefanie
      January 24, 2013 at 3:12 pm

      True, but maybe you can just hide them amongst all the glorious cheese!!

  • Amanda @ Once Upon a Recipe
    January 24, 2013 at 1:50 pm

    Shut the front door. This looks magical. Nothing like a gooey grilled cheese on a cold winter day. And then you went and added balsamic caramelized onions. Deadly!

  • Isabelle @ Crumb
    January 24, 2013 at 11:25 am

    This looks awesome… kind of like French Onion Soup in sandwich form, which is something that I am very much on board with.
    (Also, I used to tattle on my sister all the time. I saw it as my duty as her older and wiser and better-behaved sister. 😉 )

    • Stefanie
      January 24, 2013 at 3:12 pm

      HAHAHA! Exactly! We are just looking out for them.

  • Lisa Waldschmidt
    January 24, 2013 at 9:47 am

    Nice – I love grilled cheese, especially with a nutty cheese like Fontina and some fresh herbs to brighten it up.

  • kelsey
    January 24, 2013 at 9:13 am

    omg this looks dangerous…