6 skinless boneless chicken breast halves (5 to 6 ounces each)
1/2 cup balsamic vinegar
3 tablespoons olive oil
2 teaspoons coarse kosher salt, divided
1 1/2 teaspoons freshly ground black pepper, divided
2 teaspoons herbes de Provence*
1 3- to 4-ounce wedge blue cheese, cut into 6 slices
* Sold in the spice section of supermarkets and at specialty foods stores.
Place chicken in large resealable plastic bag. Whisk vinegar, 3 tablespoons oil, 1 1/2 teaspoons coarse salt, and 1 teaspoon pepper in small bowl. Add to chicken; seal bag. Chill 2 hours, turning bag occasionally.
Prepare barbecue (medium-high heat). Brush grill rack generously with oil. Arrange chicken on grill. Sprinkle with herbes de Provence, 1/2 teaspoon coarse salt, and 1/2 teaspoon pepper. Grill chicken until cooked through, about 6 minutes per side. Transfer to plates; top each with slice of cheese.