Make the batter: Combine the fish stock with 1 cup water in a bowl. Add the flour, yam, milk, baking powder, salt and sugar and mix well. Cover the batter and refrigerate for a minimum of 2 hours and a maximum of 4 days.
Make the okonomiyaki: Place 1/5 of the batter in a bowl and add 1 1/3 cups of the cabbage, 2 teaspoons of the tempura bits and 1 teaspoon of the ginger. Add 1 egg and mix very lightly until the mixture becomes marbled with white and yellow.
Place a few tiny drops oil on the griddle or in a heavy non-stick skillet and spread it. Heat the griddle to 380 degrees F., or heat the skillet over medium heat.
Pour the okonomiyaki mixture in a circular form over the oil. Place 4 pieces of squid on top of the raw batter. When one side has cooked for 7 minutes, flip the okonomiyaki and cook for another 7 minutes. Repeat the procedure with the remaining ingredients on another part of the griddle or in separate skillets.
With about 1 to 2 minutes remaining, start applying the sauces and toppings: Onto each okonomiyaki, squeeze about 2 tablespoons of the okonomi sauce, followed by the desired amount of mayonnaise. Finally, sprinkle 2 pinches of the bonito flakes and 1 pinch of the aonori on top.
Remove from heat and serve immediately.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.