Ingredients
Scale
- 4 slices of hearty bread (sourdough or French bread preferred)
- 1 large onion, thinly sliced
- 2 tablespoons unsalted butter
- 1 tablespoon olive oil
- 1 teaspoon sugar (for caramelizing the onions)
- 1 cup shredded Gruyère cheese
- 1 cup shredded Swiss cheese
- 1/2 teaspoon salt
- 1/4 teaspoon black pepper
- Optional: 1 teaspoon balsamic vinegar or white wine (to enhance flavor)
- Fresh thyme or rosemary for garnish (optional)
Instructions
- In a large skillet, melt butter with olive oil over medium heat. Add sliced onions, sugar, salt, and pepper. Cook slowly, stirring frequently, until onions are golden brown and caramelized, about 25-30 minutes. Optionally, add balsamic vinegar or white wine during the last few minutes.
- Spread caramelized French onion mixture on one slice of bread. Sprinkle half of the Gruyère and Swiss cheese over the onions. Top with the second slice of bread, pressing gently.
- Preheat a skillet or grill pan over medium heat. Butter the outside of each sandwich. Place in the skillet and cook for 3-4 minutes per side until golden brown and cheese is melted. Press down with a spatula for even contact.
Notes
- For added flavor, sprinkle fresh thyme or rosemary before grilling.
- Use a good quality bread to enhance texture and flavor.
- Ensure to cook onions slowly for best caramelization; rushing can lead to burning.
- Prep Time: 10 minutes
- Cook Time: 30 minutes
- Category: Sandwiches
- Method: Grilling
- Cuisine: French
- Diet: Vegetarian
Nutrition
- Serving Size: 1 sandwich
- Calories: 530 Kcal
- Sugar: 8g
- Sodium: 650mg
- Fat: 24g
- Saturated Fat: 14g
- Unsaturated Fat: 8g
- Trans Fat: 0g
- Carbohydrates: 58g
- Fiber: 4g
- Protein: 24g
- Cholesterol: 70mg