Combine all hoisin sauce ingredients in medium sauce pan and reduce over medium heat for 10-15 minutes, until thickened. Cool and purée in a blender. Reserve for up to one week.
Preheat grill to medium-high heat. Sear duck breast scored side down for 3-4 minutes. Turn and glaze with hoisin sauce. Cook until an instant read thermometer registers 130 degrees. Remove the duck from the grill and let rest, tented with foil.
Garnish hoisin glazed duck with flowering basil and pair with the freshest vegetables from your summer garden.