# What You'll 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
# How to Make It:
01 - In a large skillet over medium-low heat, melt 2 tablespoons butter with 1 tablespoon olive oil. Add sliced onions, salt, and pepper. Cook, stirring occasionally, for 25 to 30 minutes until deeply golden and caramelized. Stir in thyme and balsamic vinegar, then cook 1 minute longer. 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.
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 3 to 4 minutes per side until golden brown and cheese is melted. Press gently with a spatula for even toasting.
05 - Slice sandwiches in half and serve immediately.