Thyme Infused Balsamic Glazed Chicken with Caramelized Onions

Ingredients

• 1 pound uncooked boneless skinless chicken breasts, four 4 oz pieces
• 1/4 teaspoon freshly ground black pepper, divided
• 3 tablespoons all-purpose flour
• 2 teaspoons olive oil
• 1/2 teaspoon table salt, divided
• 1 egg
• 1/2 teaspoon dried thyme for flour mixture
• 2 tablespoons balsamic vinegar
• 1 small vidalia onion, cut in half lengthwise, thinly sliced
• 2 teaspoons salted butter
• 1 cup reduced-sodium chicken broth
• 1 tablespoon fresh thyme leaves