Grilled Chicken Marinated in Mango Vinegar and Tarragon

From www.napastyle.com
(Serves 4)

Ingredients
4 boneless, skinless chicken breasts halves
2 large, ripe mangoes, peeled and cut into 1/2" dice (about 2 cups)
4 cups granulated sugar
1 cup water
2 vanilla beans, minced, or 2 tablespoons pure vanilla extract
Pinch of salt
1/2 cup champagne vinegar (or white wine vinegar)
2 teaspoons finely chopped fresh tarragon or 1 teaspoon dried tarragon
Gray salt and freshly ground black pepper, to taste

Directions

Sugar syrup
Bring the sugar, water, and vanilla (if using beans) to a boil over high heat. Lower heat to a simmer and cook about 4 minutes, stirring occasionally. Let cool. Pour into blender and puree until vanilla beans are thoroughly chopped into the syrup. Strain through a fine strainer into a bowl.
If using vanilla extract, add after the sugar syrup has cooled (no need to blend).

Chicken
Prepare grill or preheat broiler to medium-high heat.
In a blender, puree the mangoes, sugar syrup, and salt. Add vinegar and taste for balance. Add more vinegar and thin with water, if necessary. Strain through a fine strainer into a bowl.

Place the chicken in the bowl. Add the tarragon and turn breasts until well covered. Season with salt and pepper (if needed).

Oil the grill or broiler rack. Cook away from the flame. Grill on one side for about 5 minutes, or until brown. Turn and baste with the mango vinegar. Continue to cook until done, about 5 minutes more. Pass the vinegar or extra mango vinegar as a table sauce.