French Onion Grilled Cheese sandwich takes well loved comfort food up a notch. If you love French Onion Soup this hot sandwich full of loads of caramelized onions and gooey melted gruyere cheese of crisp buttery bread will be a favorite.
If you love grilled cheese sandwiches and thought they couldn’t get any better this French Onion Grilled Cheese is for you.
The gooey cheese and crisp buttery bread is still there. Adding the sweet caramelized onions makes it a whole new thing!
It’s still the relaxed comfort food but with sophisticated flavors.
French Onion Grilled Cheese
What sets this grilled cheese apart is the onions. They are cooked with white wine giving them a signature flavor found in the popular French onion soup.
The soft texture is delicious and the sandwich feel fancy and relaxed at the same time.
This recipe can make two or three sandwiches depending on how thick you want the sandwiches.
To make it into three, just add two additional slices of bread, divide the onions evenly between three sandwiches.
Use 1/3 cup of grated cheese per sandwich (instead of 1/2 cups divided).
It’s great for lazy weekends or weeknights when you want something special.
How to Caramelize Onions
Like making a risotto, caramelizing onions is a bit of a labor of love. And one well worth the time.
They aren’t hard to make but to truly get them to the sweet caramelized end result it takes time.
If you read a recipe that says you can caramelize onions in 15 minutes, it’s just not true. Or they aren’t actually caramelized onions.
Caramelizing onions is browning of the sugars in the onions. Cooking them over medium heat for a longer time gives them a sweet, rich flavor and mahogany brown color.
They should not be cooked fast or over high heat which can cause them to overcook.
It requires patience, monitoring and periodic stirring.
Recipe Ingredients + Notes
Unsalted Butter. Used both in cooking the onions and to spread on the bread when making the sandwich. It does not need to be softened for caramelizing the onions. The butter for the sandwiches will spread more easily if softened or at room temperature.
Olive oil. Will be used for cooking the onions.
Yellow Onion. Choose a medium size onion (about 3 1/2 inches in diameter). Slice it uniformly so all the slices are the same thickness (refer to the recipe steps photos below).
White Wine. Use a dry white wine (versus sweet). Pinot Grigio, Pinot Gris, Sauvignon Blanc, Chardonnay that isn’t very oaky in flavor are all great choices.
Apple cider. Adding some apple cider creates a wonderful depth of flavor with a bit of sweetness that is perfect for the onions.
Seasonings. Salt, pepper, dried thyme, dried rosemary.
Bread. Though any type of bread can be used using bread with a more neutral flavor is best. Strong flavored whole grain breads can overpower the lighter flavors of the caramelized onions and the melted cheese.
Gruyere cheese. This is the classic cheese used in French onion soup. It’s delicious however if preferred you can substitute another mild flavored cheese you love.
How to Make it – Step-by-Step
STEP 1. Caramelize the onions.
In a large skillet or saucepan, melt 2 tablespoons unsalted butter and add the olive oil. Note: using a heavy bottom pan will help prevent over cooking.
Add the onions (photo 1) and let the onions cook until they begin to caramelize; around 20 minutes.
Pour in the wine and cook, stirring constantly, until it evaporates; 1-2 more minutes.
Add the apple cider, spices, salt and pepper. Cook until the apple cider has evaporated (or been absorbed by the onions). This will take approximately 15 more minutes.
The onions will have a rich brown color. The color will deepen significantly in the last 5 minutes of cooking (photo 2).
Remove from the heat.
STEP 2. Make and cook the grilled cheese sandwich.
Butter one side of the 4 slices of bread.
Place 2 of the bread slices in a large skillet over medium-high heat (photo 3 – showing just one slice). Place the buttered side facing the skillet. A griddle can also be used.
Layer on top of EACH of the two bread slices:
- 1/4 cup of the grated cheese
- followed by half of the caramelized onions
- another 1/4 cup of grated Gruyere cheese, and
- topped with a second slice of bread buttered side facing up.
Cook until the bottom slice of bread is golden brown on the outside and the cheese is beginning to melt.
Flip over (photo 4) and cook until the other piece of bread is also golden brown and the cheese is melted.
Allow the sandwich to sit for a minute before eating.
Recipe FAQs + Notes
Make the sandwiches in a panini or gridle device. A panini maker, a Griddler or a waffle maker with flat reverse plates can also be used for cooking the sandwiches.
Assemble the sandwiches and cook them that way instead of in the pan or on a griddle. Depending on your device it may not be necessary to butter the sandwich bread either.
Cook the onions over medium heat. This is a cooking process you don’t want to rush but turning up the heat. Keep it on medium to let the magic happen with the onions!
More Recipes You’ll Love!
- Caramelized Onion & Fig Puff Pastry Appetizers
- Caramelized Pear Upside Down Cake
- Caramelized Roasted Pumpkin
French Onion Grilled Cheese
For the caramelized onions
- 2 tablespoons unsalted butter
- 1 tablespoon olive oil
- 1 medium yellow onion sliced
- ⅓ cup white wine
- ⅓ cup apple cider
- ¼ teaspoon kosher salt
- 1/8 teaspoon ground black pepper
- ¼ teaspoon dried thyme
- ¼ teaspoon dried rosemary
For the sandwich
- 4 slices bread regular or gluten-free
- 1 cup grated gruyere cheese
- 2 tablespoons unsalted butter
How to Make the Caramelized Onions
- Melt the butter and add the olive oil in a large saucepan over medium heat. Add the onion and cook, stirring periodically, until they begin to caramelize, around 20 minutes.
- Pour in the white wine and cook until the wine has evaporated completely, around 1-2 more minutes.
- Pour the apple cider, thyme, rosemary, salt and pepper. Cook until the apple cider has evaporated and the onions have a rich caramelized color, around 15 minutes. Remove from heat.
Making the Grilled Cheese sandwich
- Spread the butter over one side of the sandwich bread slices.
- Place two slices of bread, buttered side down, on a large hot skillet or griddle.
- Sprinkle ¼ cup of the grated cheese on each of the two bread slices in the pan (1/2 cup total cheese). Follow with half of the caramelized onions (half on each slice). Sprinkle ¼ cup of the cheese onto each pile of onions followed by a slice of bread with the buttered side facing up.
- Cook until the bread is golden brown and the cheese is beginning to melt. Flip over and cook until the other side of the sandwich is golden brown and the cheese if fully melted.
● You can also add some apple slices to the sandwich to give a crunch and some extra freshness.
● You can swap the butter for mayo (for the spread) to give an even deeper golden hue.