For marinade: mix together scallions, mirin, vinegar, sugar, soy sauce, 1 tsp oil and red pepper flakes. Add chicken and chill at least 2 hr. or overnight.

Remove chicken from marinade and pat dry. Discard marinade.

In large skillet, heat remaining tsp of oil. Add chicken and brown lightly on each side. Add broth and bring to boil.

Reduce heat and simmer covered until chicken is cooked through and liquid is syrupy. Turn chicken to coat.