Add the remaining 1 tablespoon of olive oil to the skillet. Add the onion and the remaining 1 tablespoon of ginger; cook over moderate heat for 5 minutes, stirring frequently. Add the coconut milk, stock and curry paste and bring to a boil, stirring. Simmer the sauce for 5 minutes, until thickened. Add the chicken, 1/3 cup of the basil, 2 tablespoons of the cilantro and the scallions; simmer until the chicken is cooked through, 5 minutes. Season with salt and pepper.