Prepare your grill
Pound the chicken breast to about 1/2 inch thickness
Brush each chicken breast with approximately 1 tbsp. pesto
Fold the chicken breast so the pesto remains completely inside
Grill chicken until internal temperature reaches 165 degrees (depends on your grill, but this is often 5-7 minutes per side for our grill)
Meanwhile, make the glaze.
Bring balsamic to a boil, lower heat to a simmer and add honey & mustard.
Simmer for about 5 minutes or until balsamic has thickened a bit.
Pour over grilled chicken.