# Needed Ingredients:
→ Caramelized Onions
01 - 2 large yellow onions, thinly sliced
02 - 2 tablespoons unsalted butter
03 - 1 tablespoon olive oil
04 - 1/2 teaspoon salt
05 - 1/4 teaspoon freshly ground black pepper
06 - 1 teaspoon fresh thyme leaves
07 - 1 teaspoon balsamic vinegar
→ Sandwiches
08 - 4 slices rustic country bread
09 - 4 ounces Gruyère cheese, grated
10 - 1 tablespoon unsalted butter, softened
# Preparation Steps:
01 - In a large skillet over medium-low heat, melt butter with olive oil. Add sliced onions, salt, and pepper. Cook while stirring occasionally for 25 to 30 minutes until onions are deeply golden and caramelized. Stir in thyme and balsamic vinegar, then cook for 1 additional minute. Remove from heat.
02 - Lay out bread slices. Evenly distribute caramelized onions on two slices. Top each with half of the grated Gruyère cheese. Place remaining bread slices on top to close sandwiches.
03 - Spread softened butter on the outside of each sandwich.
04 - Heat a non-stick skillet or griddle over medium heat. Place sandwiches in the pan and cook until golden brown with melted cheese, approximately 3 to 4 minutes per side. Press gently with spatula to ensure even toasting.
05 - Slice sandwiches in half and serve immediately.
