Brie, Chicken and Caramelized Onion Panini

Preheat the panini press. If it has a variable setting, set it to "sear" (high) - you're going to cook the chicken breasts first. Make the caramelized onions: In a saute pan on low, melt the butter, then add the sliced onions. Let them heat slowly (not saute) for 20-30 minutes, until golden brown. Add the brown sugar and balsamic vinegar, and cook another 2-3 minutes, stirring frequently. Caramelized onion will store well in the fridge for 3-4 days. Cook the chicken breast: Wash chicken breast and pat dry. Drizzle olive oil on both sides, and add a pinch of kosher salt to both sides. Put in panini press for 3-5 minutes, and check for doneness. (I like to rotate the chicken breast 90 degrees halfway through to achieve a crosshatch pattern.) Wipe down panini grill -- be careful, it's hot! Lower heat to panini temperature (low.) Assemble the panini: For each sandwich, spread olive oil on one face of both slices of bread. Add cheese, then cooked chicken breast, then carmelized onion. Top with bread, olive oil side up. Place in panini press and cook for 5 minutes. (I like to rotate it halfway through, 90 degrees for the crosshatch pattern.) Get plates ready. Remove hot panini, slice on a diagonal, and serve immediately.