Onion French Melt Sandwich
This Onion French Melt Sandwich delivers all the cozy flavors of French onion soup—sweet caramelized onions and melty Gruyère—packed into a buttery, crispy grilled sandwich.
Equipment
- Large skillet or frying pan
- Spatula
- cutting board
- sharp knife
- Butter knife or spreader
Ingredients
- 2 large yellow onions thinly sliced
- 2 tbsp butter divided
- 4 slices sourdough or French bread
- 4 oz Gruyère cheese sliced or shredded
- salt to taste
- black pepper to taste
- 1 tsp fresh thyme optional
Instructions
- Slice the onions thinly and separate the rings.
- Melt 1 tablespoon butter in a large skillet over medium heat. Add the onions and cook 20–25 minutes, stirring occasionally, until deeply golden and caramelized. Season with salt, pepper, and thyme (if using). Transfer onions to a plate.
- Butter one side of each bread slice with the remaining 1 tablespoon butter.
- Assemble 2 sandwiches: Place 2 slices of bread butter-side down. Top each with half the Gruyère, then spoon caramelized onions over the cheese. Add remaining Gruyère on top, then close with the remaining bread slices, butter-side up.
- Heat a clean skillet over medium. Cook sandwiches 3–4 minutes per side until the bread is golden and crisp and the cheese is melted. Reduce heat slightly if the bread browns before the cheese melts.
- Rest 1 minute, then slice and serve hot.
Notes
Don’t rush the onions—medium heat and patience make them sweet and golden (too-hot heat burns them). Swap Gruyère with Swiss if needed. Make-ahead: caramelize onions up to 4 days ahead and refrigerate; rewarm in a skillet before assembling. For extra tang, add a thin swipe of Dijon mustard inside the bread.
Nutrition
Calories: 620kcal | Protein: 26g | Saturated Fat: 18 | Cholesterol: 95mg | Sodium: 950mg