Begin by heating 1 tablespoon of unsalted butter in a skillet over medium heat. Once melted, add the thinly sliced medium onion along with a pinch of salt. Stir occasionally for about 10 minutes until the onions turn golden and soft. Mix in a splash of balsamic vinegar and cook for an additional 2-3 minutes until the onions are caramelized. Remove from skillet and set aside.

In the same skillet, lower the heat to medium-low and layer two slices of sourdough bread. Sprinkle half of the shredded sharp cheddar cheese onto the bread, followed by the caramelized onions, apple slices, and pear slices. Top with the remaining cheddar, then place two more slices of bread on top to complete each sandwich.

Increase the heat back to medium and add the remaining tablespoon of butter to the skillet. Once melted and sizzling, carefully place one assembled sandwich in the skillet. Grill for approximately 4-5 minutes until the bread is golden and crispy. Flip the sandwich to grill the other side for another 4-5 minutes until the cheese is gooey and melted.

Once both sides of the sandwiches are perfectly golden and the cheese has thoroughly melted, remove them from the skillet. Allow to cool slightly on a cutting board before slicing in half. Serve warm and enjoy your Pear & Apple Grilled Cheese with Caramelized Onions.