Grilled Cheese With Caramelized Onion Recipe

Grilled cheese sandwich with caramelized onion

FotoosVanRobin / Moment / Getty Images

Prep: 10 mins
Cook: 30 mins
Total: 40 mins
Servings: 4 servings
Nutrition Facts (per serving)
611 Calories
42g Fat
35g Carbs
25g Protein
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Nutrition Facts
Servings: 4
Amount per serving
Calories 611
% Daily Value*
Total Fat 42g 53%
Saturated Fat 21g 106%
Cholesterol 100mg 33%
Sodium 1072mg 47%
Total Carbohydrate 35g 13%
Dietary Fiber 5g 16%
Total Sugars 8g
Protein 25g
Vitamin C 2mg 12%
Calcium 687mg 53%
Iron 2mg 10%
Potassium 296mg 6%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

These delicious grilled cheese sandwiches with caramelized onions are easy to make, especially if you make the caramelized onions ahead of time. Make a batch and keep in the fridge for 3 to 4 days. You can add them to everything from meatloaf to scrambled eggs. We like to add sliced garlic to the onions during the last 5 minutes of cooking time for another layer of flavor.

There's nothing better or more satisfying, or simpler to make than a grilled cheese sandwich or any hot sandwich. These recipes can be changed any way you'd like. Use a different bread, a different cheese, more cheeses, or add veggies such as sliced tomatoes, sautéed bell peppers, or spinach or other greens. You could also add some sautéed apples or pears for a sandwich reminiscent of fall. Add some crisply cooked bacon or thinly sliced ham for a fabulous variation. If you change the recipe, write down the changes so you can reproduce your masterpiece.

These easy sandwiches can be served with nothing but a cold glass of milk, but you could add a green salad or a fruit salad for a complete meal.

“I’ve made a lot of grilled cheese in my life, I like to think of myself as an authority on the topic, so I hope you take me seriously when I say this recipe is fantastic. The caramelized onions really help bring out a sweet taste along with that cheesy goodness.” —Noah Velush-Rogers

Grilled Cheese With Caramelized Onion Sandwiches/tester image
A Note From Our Recipe Tester


  • 2 medium onions, thinly sliced lengthwise

  • 2 tablespoons olive oil

  • 1 tablespoon unsalted  butter

  • 1 tablespoon lightly packed brown sugar

  • 1/2 teaspoon kosher salt

  • 1/4 teaspoon freshly ground black pepper

  • 8 slices whole wheat bread

  • 8 slices Gruyere, or havarti cheese

  • 1/4 cup unsalted butter, softened

Steps to Make It

  1. Gather the ingredients.

  2. Sauté the onions, olive oil, and butter in a large heavy-duty skillet over medium heat, stirring frequently, until onions start to sweat and reduce, about 10 minutes.

  3. Reduce the heat to low and cook, stirring occasionally, until onions become golden, about 15 to 25 minutes longer. Toward the end of the cooking time, watch the onions carefully and stir more often so they don't burn.

  4. Sprinkle the onions with sugar, salt, and pepper, cook for another 2 to 3 minutes. Remove from the heat and let cool to room temperature.

  5. To make sandwiches, place the bread on a work surface. Top 4 slices of the bread with a slice of cheese, then spread evenly with a few spoonfuls of the caramelized onion mixture.

  6. Top with another slice of cheese. Top with remaining slices of bread to make 4 sandwiches.

  7. Spread the outsides of the sandwiches evenly with the softened butter. Add the sandwiches to large heavy-duty skillet over medium heat in batches, if necessary. Cover the pan and cook, turning once, until the bread is toasted and the cheese melts. Alternatively, use a panini grill or dual contact indoor grill. Serve immediately.

Storing Caramelized Onions

Caramelized onions can be store, covered, in the fridge for 3 to 4 days. You can freeze caramelized onions for longer storage, up to 3 months. To thaw, let them stand in the fridge overnight.