Heat the oil in a large saucepan over medium-high heat and add the cumin seeds, and curry leaves; they should sizzle upon contact with the hot oil. Quickly add the ginger, garlic, green chili, coriander and cook, stirring, about 2 minutes.
Add the cabbage, and salt, cover the pan and cook, stirring as needed, over medium- high heat for first 2 to 3 minutes and then over medium-low heat until the cabbage is tender, about 10 minutes. Mix in the cooked lentil and cilantro during the last 5 minutes of cooking. Transfer to a serving bowl, sprinkle the garam masala on top, and serve.