# What You Need:
→ 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
# Directions:
01 - In a large skillet over medium-low heat, melt 2 tablespoons butter with olive oil. Add sliced onions, salt, and pepper. Cook, stirring occasionally, until deeply golden and caramelized, approximately 25 to 30 minutes. Add thyme and balsamic vinegar, cooking for 1 additional minute. Remove from heat.
02 - Lay out bread slices. Distribute caramelized onions evenly on two slices, then top each with half of the grated Gruyère. 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 pan and cook until golden brown with melted cheese, approximately 3 to 4 minutes per side, pressing gently with a spatula for even toasting.
05 - Slice sandwiches in half and serve immediately.