If you’re looking for a little gourmet spin on a classic grilled cheese, try this caramelized onion grilled cheese sandwich recipe! It’s brimming with two types of cheese, perfectly cooked caramelized onions and blueberry jam. After being pan fried, the outside is golden brown and crispy while the inside is creamy, cheesy, savoury and sweet. Talk about a deliciously easy comfort food meal!
I’ve been using a lot of caramelized onions lately (and for good reason!). They’re just so versatile and tasty.
Isn’t it amazing how much flavour you can get out of the humble onion? And simply by changing the method of cooking, it changes their taste and texture. For instance, fried onions are quite different than caramelized onions.
Though there are various ways to cook onions, today’s star ingredient of this grilled cheese is, of course, caramelized onions.
Even though it’s technically spring here in Newfoundland, the weather is still on the cooler side (as a matter of fact, we often have snow in May!), so it’s no surprise that I’m still enjoying all sorts of comfort food, like this ooey gooey caramelized onion grilled cheese sandwich.
Just curious, what way do you cut your sandwich: horizonal or diagonal? Or do you even cut it in half at all?
Fan of grilled cheese sandwiches? Check out this pickle grilled cheese!
Caramelized Onion Grilled Cheese Ingredients
- Caramelized onions: To make caramelized onions you’ll need butter, olive oil, onions, salt and black pepper.
- Sandwich bread: Use your favourite variety. It doesn’t have to be anything fancy, just something you enjoy. For an extra special treat, grab some bread from your local bakery, freshly made.
- Jam: Again, use your favourite variety. I love blueberry jam, but strawberry or apricot would work.
- Cheese: Two varieties of cheese are used in this recipe: a soft creamy cheese, like Boursin (not sponsored) or a similar style/brand, as well as mozzarella cheese.
- Butter or margarine: Used for the outside of the bread and pan frying the sandwiches.
How To Make It
Here is an overview of how to make a caramelized onion grilled cheese sandwich recipe (full details are in the recipe card below):
Caramelize the onions
Caramelize the onions in a skillet until they’re tender and a deep golden brown colour.
Assemble the sandwiches and pan fry
- For each sandwich, spread some jam on one slice of bread and Boursin (or similar style/brand) on another slice of bread.
- Top the jam with caramelized onions and shredded mozzarella cheese.
- Place the other slice of bread over top to form the sandwich, then spread some butter over top.
- Melt some butter in a skillet.
- Place the sandwiches in the skillet (non-buttered side down) and cook until they’re golden brown and crispy on one side.
- Flip the sandwiches and continue to cook them on the other side until they’re golden brown and crispy on the other side and the cheese is nice and melty inside.
What To Serve With It
- Creamy tomato basil soup
- Pasta salad
- Blueberry spinach salad
- Potato chips
- Baked fries
- Veggie sticks and dip
Tips and Variations
- Save time: To save time the day of making the sandwiches, you can make the caramelized onions a day ahead and store them in an airtight container in the fridge.
- Watch the heat: Monitor the heat as you are pan frying the sandwiches as to not burn them. The goal is to get a lovely golden brown and crispy exterior and a melty cheese interior. If the heat is too high, you’ll likely brown the outside too quickly before the cheese has a change to melt (and nobody wants that).
- Use your favourite jam: I used store-bought blueberry jam. Feel free to use another variety, either store-bought or homemade, whatever you enjoy best!
- Mix up the cheese: If you don’t have Boursin cheese (or a similar style or brand), you can substitute with goat cheese.
- Add protein: For extra heartiness, add some protein to your grilled cheese sandwich, like crispy prosciutto or crispy bacon. Both are on the salty side and work great with the caramelized onions and sweet jam.
More Recipes Using Caramelized Onions
If you you try this caramelized onion grilled cheese sandwich recipe, be sure to leave a comment below!
Caramelized Onion Grilled Cheese Sandwich
Ingredients
Caramelized Onions
- 2 tablespoons butter
- 1 tablespoon olive oil
- 1 pound yellow onions, peeled and slice about ⅛-inch to ¼-inch thick
- Hot water, as needed to deglaze the pan
- Salt, to taste
- Freshly ground black pepper, to taste
Other Grilled Cheese Sandwich Ingredients
- 8 slices sandwich bread
- 4 tablespoons blueberry jam, or your favourite variety
- 4 tablespoons Boursin cheese, or similar brand/variety (I like to use a flavoured version, such as one with herbs)
- 2 cups shredded mozzarella cheese
- 4 tablespoons butter or margarine, divided
Instructions
Caramelized Onions
- Heat butter and olive oil in a large frying pan (like a cast-iron pan or enameled cast-iron pan) over medium-low heat.
- Add the onions to the frying pan, stirring to coat in the butter/oil. Cook the onions for 40 to 45 minutes, stirring every 5 to 10 minutes, until they're tender and a deep golden brown colour. Periodically while cooking, deglaze with a little hot water (about 3 to 4 tablespoons at a time) and use a wooden spoon to scrape up the brown bits that have accumulated in the bottom of the pan and incorporate them back into the onions).Note: Once the water is added, I like for all of it (or mostly all of it) to be evaporated before adding more. The water not only helps to cook the onions, but helps to deglaze the pan.Note: As you are cooking the onions, if you sense that your heat is too high, reduce it.Note: Total cook time could vary, depending on the thickness of your onions, the cooking temperature and the desired colour.
- Once you've reached your desired doneness, deglaze with a little water one more time, scraping up all the brown bits and stirring into the onions.
- Season with salt and black pepper to taste.
Sandwich Assembly
- Spread blueberry jam over one side of four slices of bread. Spread Boursin cheese over one side of the other four slices of bread.
- Divide the caramelized onions between four of the slices of bread (on top of the blueberry jam), then sprinkle the mozzarella cheese over top of the caramelized onions. Place the other slices of bread over top (with the Boursin cheese on the inside) to form the four sandwiches. Spread butter or margarine over top of each sandwich (½ tablespoon per sandwich).
Pan Fry the Sandwiches
- Melt 1 tablespoon of butter or margarine in a large skillet over medium-low heat. Once melted and foamy, add two sandwiches (the non-buttered side down). Cook the sandwiches for about 3 to 5 minutes or until they're golden brown and crispy. Then carefully flip the sandwiches and continue to cook them for another 3 to 5 minutes or until the other side is golden brown and crispy and the cheese is melty (watch carefully and adjust the heat as necessary as to not burn your sandwiches).
- Repeat the process to cook the remaining two sandwiches, adding the remaining 1 tablespoon of butter or margarine first.
- Once all the sandwiches are done, serve and enjoy!
Notes
- Save time: To save time the day of making the sandwiches, you can make the caramelized onions a day ahead and store them in an airtight container in the fridge.
- Watch the heat: Monitor the heat as you are pan frying the sandwiches as to not burn them. The goal is to get a lovely golden brown and crispy exterior and a melty cheese interior. If the heat is too high, you’ll likely brown the outside too quickly before the cheese has a change to melt (and nobody wants that).
- Use your favourite jam: I used store-bought blueberry jam. Feel free to use another variety, either store-bought or homemade, whatever you enjoy best!
- Mix up the cheese: If you don’t have Boursin cheese (or a similar style or brand), you can substitute with goat cheese.
- Add protein: For extra heartiness, add some protein to your grilled cheese sandwich, like crispy prosciutto or crispy bacon. Both are on the salty side and work great with the caramelized onions and sweet jam.
A note on times provided: appliances vary, any prep and/or cook times provided are estimates only.
© Girl Heart Food Inc. Photographs and content are copyright protected.
Tried this recipe?
If you do make this recipe, thank you!! It would mean so much if you could leave a comment below. Love to know how you enjoyed it, and it helps other readers too!
David @ Spiced says
Oh what a fun idea! When I see a pile of caramelized onions, I usually think French Onion Soup…but this sandwich sounds delicious. And adding a bit of jam in there, too? This grilled cheese sammich is calling my name!!
Dawn | Girl Heart Food says
Thanks so much, David! It’s such a yummy combo!
Michelle says
This is the best kind of grilled cheese! Ooey, gooey, salty an slightly sweet! I’ll take mine with a side of tomato soup 🙂
Dawn | Girl Heart Food says
Thank you very much, Michelle! It’s a fantastic combo with the tomato soup. 🙂