Mix together in a sealable container or plastic bag:

 1/4 Cup Olive Oil
 1/4 Cup Soy Sauce (low sodium)
 1/2 Cup Marsala wine
 1 Tablespoon Liquid Smoke
 1 Tablespoon crushed dried Tarragon

Add:

 6 boneless skinless Chicken breast halves.

Seal bag or container. Rotate bag until all of the Chicken breasts are covered with the marinate.
Marinate overnight in a refrigerator.

Remove chicken from the marinate, retain the liquid to make the gravy (see below).

Heat grill to 500-F, brush grill with some olive oil.
Add the chicken breasts.
Reduce heat to medium-hot (325-375-F).
Cook for 25-30 minutes, turning and marinating every 5 minutes.

Remove from grill.
Let stand 10 minutes before serving.

Marsala Gravy

Place marinate in a small sauce pan.
Add and wisk:
 2 Tablespoons brown sugar
 2 teaspoons cornstarch

Bring to a boil and cook until it thickens. Serve under and over the grilled chicken.