Combine raspberry vinegar, oil and seasoning in a shallow pan.  Add chicken breasts and marinate at least 30 minutes in refrigerator.

Strain raspberries, reserving juice and discarding pulp.  Add corn starch to raspberry juice.  Cook in a medium saucepan until sauce comes to a boil, continue cooking 1 minute.  Reserve and keep warm.

Remove chicken from marinade. Discard marinade. Grill, broil or sauté chicken until done, about 12 to 20 minutes . Swirl plate with raspberry sauce, top with chicken breast.  Serve with new potatoes or seasoned rice.