French Onion Grilled Cheese

Instructions

1. Caramelize the onions
   Heat olive oil in a large skillet over medium-low heat. Add sliced onions, thyme, bay leaf, and a pinch of salt. Cook slowly, stirring occasionally, for about 20-25 minutes until onions are deeply caramelized. Add brown sugar and beef broth/wine, scraping up any browned bits from the bottom of the pan. Cook for another 2-3 minutes until liquid is absorbed. Remove bay leaf and set aside.
2. Prepare the cheese mixture
   In a medium bowl, combine the grated Gruyère and Emmental cheeses. Mix in the Dijon mustard and Worcestershire sauce until well incorporated. Season with a little black pepper.
3. Assemble the sandwiches
   Butter one side of each bread slice. Flip four slices over (buttered side down) and divide the cheese mixture evenly among them. Top each with a generous portion of the caramelized onions, spreading them evenly. Place the remaining bread slices on top, buttered side up.
4. Grill the sandwiches
   Heat a large skillet or griddle over medium heat. Place the sandwiches in the pan and cook for 3-4 minutes per side, or until the bread is golden brown and crispy and the cheese is completely melted. If needed, lower the heat and cover with a lid to help the cheese melt without burning the bread.
5. Serve
   Cut sandwiches diagonally and serve immediately while hot and cheese is still gooey. Pair with a small side salad or bowl of tomato soup for a complete meal.