Add the cabbage, carrot, leek, soy sauce, sesame oil and pickled ginger in a bowl. Mix well and set aside.
In a mixing bowl, add the remaining ingredients. Mix well until the a smooth batter forms. Add the cabbage mix to the mixing bowl with the batter and stir well.
Heat a large non-stick frying pan on medium-high heat. Lightly brush the pan with oil (I used rice bran oil) and use a ½ measuring cup to scoop out the batter into the pan. Use the bottom of the measuring cup to for a circular batter. Cook the pancakes for a few minutes until bubbles start appearing on the top. Flip it with a spatula and cook the other side until lightly brown and crispy. Repeat for the remaining batter (I made six pancakes with the batter).
Make the sauce by combining the tomato sauce, soy sauce, sesame oil and rice wine vinegar in a small bowl.
Top with the sauce, mayonnaise (optional) and finely diced leek and enjoy.