Difficult to say, Don. My mother was German, and her typical method was to cook a long time, which resulted in very tender, yet savory dishes. Your situation seems quite the paradox - typically food that is not greasy means that the fat was hot, but that usually results in crisp exterior. Is it possible that initially the heat was high, and then lowered to "simmer" until done? That might result in skin that is sealed with the high heat, and then lower heat might result in the texture you describe.