Prepare the fillings: add 2 tablespoons of oil to the skillet over medium heat. Add the cumin seed and cook for 2 minutes, until they begin to brown. Add the onions, cook, stirring frequently, until softened and lightly browned, 8 minutes. Stir in the ginger, green lentils and 2 cups of vegetable broth.lower the heat. until liquid evaporates, add salt and pepper to your taste. add dry red lentils later, (they cook faster than greens) cook until tender