This French Onion Grilled Cheese recipe features all of the flavors of French Onion soup that you love stuffed into a easy-to-eat grilled cheese sandwich. Made with caramelized onions, Swiss cheese, and parsley, you’ll love this twist on a classic soup dish for lunch or dinner!
My Favorite Soup Becomes a Grilled Cheese Sandwich
French onion soup is one of my all-time favorite soups. It’s rich, full of flavor, and loaded with sweet and savory caramelized onions. And for this recipe, I decided to marry my favorite soup with the ultimate comfort food — grilled cheese. And if you ask me, bread, cheese, and caramelized onions were meant to be together. If you love French Onion Soup, you will love this grilled cheese.
This is an extremely simple recipe for french onion grilled cheese that anyone can make. You only need four ingredients and less than 45 minutes to make it. (Including the time it takes to cook those onions low and slow!)
If you like this recipe, then you’ll love my Warm French Onion Soup Dip!
- Butter: You’ll need unsalted (softened to room temperature) to both butter the bread and cook the onions.
- Extra Virgin Olive Oil: Also for cooking the onions so the butter doesn’t burn.
- Onion: You can use any type of onion you like. Traditionally, French onion soup is made with red onions or a mixture of red and sweet onions. I like using white.
- Bread: I like using whole wheat or sourdough because they hold up well to the heavy ingredients inside and the pan-frying process. White might fall apart or get too mush.
- Swiss Cheese: Gruyere is typically used in French onion soup, but I prefer the milder taste of Swiss. Just make sure to use sliced cheese and not shredded!
- Parsley: I like to add fresh chopped parsley to the caramelized onions after they’ve cooked. They add a nice, bright, fresh flavor to the rich onions and cheese. You can also garnish the sandwiches with some chopped parsley when serving.
- Beef Stock: You can serve this sandwich with some warm beef stock or broth, if desired. Turns this French onion grilled cheese into a French dip of sorts!
How To Caramelize Onions
The most important step in this recipe is caramelizing the onions. They need to cook for at least 30 minutes to develop that dark brown hue and sweet taste. Caramelized onions are good in anything — soup, dip and now sandwiches!
First, add the unsalted butter and olive oil to a medium skillet over low-medium heat.
Once the butter has melted, add the onions and cook for 30 minutes (low and slow). Try not to stir your onions to much. Keep them in a thin layer, and stir every so often until they achieve the signature dark brown color we’re looking for.
Add parsley to the caramelized onions, stir, and set aside in a heat-safe bowl.
How To Make the Best Grilled Cheese Sandwich
This French Onion Grilled Cheese is super simple to make. With this recipe, you’ll get all of the flavors of French Onion Soup you love in a quicker weeknight version!
- First, prepare you caramelized onions as directed above, and set aside.. Lightly wipe out your pan to remove any burned bits, but do not scrub, or else you’ll loose all of that glorious caramelized onion flavor.
- Place the generously buttered pieces of bread in a large skillet or griddle to brown.(I used whole wheat, but sourdough would also work well.)
- Then, assemble your sandwiches by layering the unbuttered sides with Swiss cheese and the caramelized onions. (I used extra thin slices of Swiss cheese, which is why this French Onion Grilled Cheese recipe calls for 6 slices on each sandwich. You can use less if you are using regular slices of Swiss cheese.) When the cheese has melted, put sandwiches together and take out of the pan.
- Slice in half, and serve immediately with a side of hot beef broth, if desired. Enjoy!
This recipe only yields two sandwiches, so I don’t actually recommend storing or freezing this French Onion Grilled Cheese recipe. Just enjoy it all hot and fresh from the skillet!
You can make a big batch of caramelized onions and store them in the fridge or freeze them to use later. Just be warned that they may break down in the thawing process. (But the flavor ill still be there!)
More Easy Sandwich Recipes To Try
- Grilled Hawaiian Chicken Sandwich
- Freezer Breakfast Sandwiches
- Blackened Salmon Sandwich with Grilled Corn Salsa
- Slow Cooker Pulled Pork Barbecue Sandwich
- Italian BLT Grilled Cheese
French Onion Grilled Cheese
- 1/2 tablespoon unsalted butter softened, plus more for buttering bread
- 1/2 tablespoon extra virgin olive oil
- 1 medium onion thinly sliced
- 4 slices whole wheat or sourdough bread
- 1 teaspoon fresh parsley chopped
- 6 slices Swiss cheese sliced very thin
- warm beef stock for dipping if desired
- Add butter and oil to a medium skillet.
- Add onions and cook over low-medium heat for 30 minutes. Try not to stir the onions too much. The onions should be a dark brown color.
- Add parsley to the caramelized onions and set aside.
- Butter each slice of bread. Place buttered side down on a large skillet or griddle.
- Add 3 extra thin slices of cheese on each side. (6 slices on each sandwich total).
- Place onions on one side of bread. When the cheese has melted put sandwiches together and take out of the pan.
- Cut in half and serve immediately with a side of hot beef broth if desired.