Grown-Up Grilled Cheese Sandwich

from 3 votes

Grown-Up Grilled Cheese with Caramelized Balsamic Onions from

Everyone seems to have an opinion when it comes to what exactly makes for the best grilled cheese sandwich. Do you slather the bread with butter or mayo? Do you double up on cheese or go for a single slice? Do you start with a hot griddle or a cold skillet?

Life is full of questions. Do we really have to turn making a sandwich into a war of do’s and don’ts? You could sous vide it for all I care, just as long as the end result doesn’t lose an ounce of its ooey-gooey appeal. And ooey-gooey appeal is one thing this grown-up grilled cheese sandwich is not lacking.

This recipe, which stars tangy caramelized balsamic onions, was a custom creation for Joanna Goddard, a fellow blogger who asked if I’d share my take on an easy weeknight meal on her popular blog, A Cup of Jo. I was thrilled to dream up this spin on a classic grilled cheese, which has become my go-to dinner on nights when there’s no time for the slow cooker and no patience for takeout. And in the spirit of no rules, I will refrain from telling you what else you could tuck between those two toasty slices of bread. (Cough … bacon … cough … avocado.)

Grown-Up Grilled Cheese with Caramelized Balsamic Onions from

Grown-Up Grilled Cheese with Caramelized Balsamic Onions from

Grown-Up Grilled Cheese with Caramelized Balsamic Onions from

Grown-Up Grilled Cheese with Caramelized Balsamic Onions from

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Main Course

Grown-Up Grilled Cheese Sandwich

Add a tasty twist to a comfort food classic with this recipe for Grown-Up Grilled Cheese Sandwich.
Author: Kelly Senyei
5 from 3 votes
Grown-Up Grilled Cheese with Caramelized Balsamic Onions from
Prep Time 5 minutes
Cook Time 40 minutes
Total Time 45 minutes
Servings 2 sandwiches


For the caramelized onions:

  • 2 teaspoons vegetable oil
  • 1 large onion, thinly sliced
  • 1 teaspoon salt
  • 1/8 teaspoon black pepper
  • 2 Tablespoons sugar
  • 1/4 cup balsamic vinegar

For the grilled cheese:

  • 1 Tablespoon unsalted butter
  • 4 slices bread (such as sourdough or brioche)
  • 4 slices sharp cheddar cheese
  • 1 cup kale leaves


Make the caramelized onions:

  • Heat the vegetable oil in a medium saucepan over medium-low heat. Add the sliced onions, salt and pepper and cook, stirring occasionally, until the onions are very soft, about 10 minutes.
  • Add the sugar and continue cooking the onions for 5 more minutes.
  • Add the balsamic vinegar and reduce the heat to low. Continue cooking the onions, stirring occasionally, for about 15 minutes until they are very soft and dry.

Assemble the grilled cheese:

  • Slather one side of all four slices of bread with the butter and set them aside.
  • Assemble one of the grilled cheese sandwiches by stacking one slice of cheese atop one slice of bread (the non-buttered side) and topping it with half the caramelized onions, half the kale leaves and a second slice of cheese. Top it with another buttered slice of bread (buttered side on top). Repeat the assembly process for the second grilled cheese sandwich.
  • Heat a large skillet or sauté pan over medium heat. Place each sandwich on the skillet and cook until the bread is toasted and golden and the cheese begins to melt. Flip each sandwich once and continue cooking until the opposite side of bread is toasted. Slice and serve immediately.
  • ★ Did you make this recipe? Don't forget to give it a star rating below!


Calories: 357kcal, Carbohydrates: 53g, Protein: 8g, Fat: 12g, Saturated Fat: 7g, Cholesterol: 17mg, Sodium: 1488mg, Potassium: 382mg, Fiber: 3g, Sugar: 22g, Vitamin A: 3520IU, Vitamin C: 44.3mg, Calcium: 163mg, Iron: 2.8mg


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Recipe by Kelly Senyei of Just a Taste. Please do not reprint this recipe without my permission. If you'd like to feature this recipe on your site, please rewrite the method of preparation and link to this post as the original source.

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  1. 5 stars
    I’ve always been a grilled cheese purist. When I was little I amused my family when I called it a “cheese grilled,” but that was indicative of how forward I wanted the cheese to be — even at 4 haha. I don’t fix grilled cheese much these days because I have no self control and don’t have the household budget to widen all the doors lol. But I took the time to play this one out, because I made some rosemary bread and had baby spinach and wanted something different. Oh my God. It was worth all the extra prep. What an amazing marriage of tastes. Tyvm.

    1. Hi Cammie – You can find the estimated nutritional info by clicking on the purple button below the recipe that says ESTIMATED NUTRITION INFORMATION. :)

  2. LOVELY recipe and planning to make this tonight. Dumb question but red, white, or yellow onions? It looks like white but just wanna double check. :) Thanks!!

  3. Looks delicious.. Will definetely give it a try and would love to post it in my blog with credits to u:)

  4. This was a delicious sandwich and I made enough caramelized balsamic onions to make more sandwiches later in the week. YUM!!!

  5. My picky husband and my experimental palate BOTH ADORED your grilled cheese recipe! He said “This is the best damn grilled cheese EVER.” Mission accomplished.

  6. The balsamic onions sound delicious sandwiched between all the cheesey goodness!!

  7. This recipe reminds me of a ‘wichcraft inspired grilled cheese I used to make. Love the combo of grilled onions, balsamic vinegar, and cheese in a sandwich. I have done it with gruyere cheese and rye bread – so delicious!

  8. Why, oh why do I torture myself with amazing food pictures like this sandwich when my stomach is growling for lunch? It looks sinfully delicious!

  9. I love, love, love caramelized onions! They’re so simple and add such great flavor to any dish. I’ll definitely be trying them on a grilled cheese next time. Thanks for sharing. Cheers, Rebecca

  10. Kelly, I think this sandwich is calling my name! I love the combination of caramelized onions, cheese and kale.

  11. Caramelized onions with sharp cheddar smushed into a sandwich and grilled sounds like heaven.

  12. Grilled cheese is one of the best comfort foods any way your slice it! Who can say “no” to a grilled cheese loaded with caramelized onions? I mean, C’mon!!

  13. Anything with caramelized onions on it has my vote! And, I’m sort of a grilled cheese addict. Thanks for the recipe!

  14. OMG–the onions, the kale, the cheese. This looks like the most incredible grilled cheese I’ve ever seen!

  15. caramelized onions are everything!!! I’d prob throw some arugula on here, just cause I’m not the kale type, but hot damn these look fabulous!

  16. I had to add this to my Best Vegetarian Sandwiches board! And a simple replacement of vegan cheddar cheese could make this a delicious vegan treat too. Love it!

  17. ahhhhhh you have hit me right in the middle of my first ever grilled cheese phase!!! I LOVE IT!

  18. I. DIE. Kelly, your grilled cheese sandwich definitely looks THE BEST! Divine. Love the caramelized onions with the balsamic and kale. Thanks for sharing. Pinning!

  19. WOW this looks delicious! I like the idea you can still have a childhood favourite but make it applicable to adult life

  20. I love grilled cheese and your grownup version looks wonderful!

    I created some brownies for Joanna last spring and seeing your post reminds me of that project :)