Heat a nonstick pan with 2 teaspoons oil until hot. Add 1/4 cup pancake mixture and gently shake the pan to form a round pancake. Cook until the bottom set, 30 seconds to 1 minute. You can add a small pinch of black sesame onto the pancake, if using. Flip to cook the other side until the pancake just set, for another 30 seconds. Transfer to a plate and cook the rest pancakes by using the same method.