Grown-Up Grilled Cheese Sandwiches
Not your ordinary grilled cheese, this one is filled with Gruyère, sweet caramelized onions and peppery arugula. Pair it with lentil soup for a satisfying supper.
- 2 Tbs. olive oil, plus more for brushing
- 1 large yellow onion, sliced 1/4 inch thick
- Kosher salt and freshly ground pepper, to taste
- 8 slices sweet batard, cut on the bias 1/2 inch thick
- 4 tsp. Dijon mustard
- 10 oz. Gruyère cheese, sliced
- 1/2 oz. arugula
- Smoky Lentil Soup for serving
In a griddle pan over medium heat, warm the 2 Tbs. olive oil. Add the onion and cook, stirring occasionally, until caramelized, about 30 minutes. Season with salt and pepper and transfer to a bowl. Wipe out the pan with paper towels.
Brush one side of each bread slice with olive oil. Turn the slices over and spread each with 1/2 tsp. mustard. Place half of the cheese on 4 of the bread slices. Top evenly with the caramelized onions and then the remaining cheese. Top each sandwich with one of the remaining bread slices, oiled side up.
Preheat the griddle pan over medium-high heat. Working in batches, place the sandwiches on the pan and cook, turning once, until the bread is golden brown and the cheese is melted, 2 to 3 minutes per side. Transfer the sandwiches to a cutting board, gently open them and arrange the arugula on top. Close the sandwiches, cut them in half and serve immediately with smoky lentil soup. Serves 4.