| 1 | Combine both stocks and vermouth in heavy med. saucepan. |
| 2 | Boil over high heat until reduced to ?cup, about 25 mins. |
| 3 | Add all mustards and whisk to blend. |
| 4 | Simmer until slightly thickened, about 3 mins. |
| 5 | Season sauce to taste with pepper. |
| 6 | (can be prepared 1 day ahead. |
| 7 | Cover and refrigerate. |
| 8 | Bring to simmer before serving). |
| 9 | Prepare barbecue (med-high heat) or preheat broiler. |
| 10 | Rub chicken breasts with garlic. |
| 11 | Grill chicken until cooked through, about 4 mins. |
| 12 | Per side. |
| 13 | Transfer chicken to plates. |
| 14 | Spoon sauce over and serve. |
