In a big bowl, whisk flour and Dashi (fish broth) together until smooth. Stir egg and yam into flour mixture. Season it with salt and soy sauce.

Add cabbage, onions, and ginger to the batter and mix. Set aside.

Heat oil in a frying pan at medium heat, and add Chuka Men noodles. Sprinkle water and cover for a minute. Then loosen noodles and stir-fry. Add salt and pepper and Yakisoba sauce. Set aside.

Heat oil in a skillet, pour a quarter of the pancake batter into an 8" circle. Put half of Yakisoba noodles on top. Cover the Yakisoba with another quarter of the batter and flatten the top a little. Lay 3 pieces of pork slices on it. Fry at medium heat until the bottom becomes golden brown, about 5-7 minutes.

Flip to fry the other side until the pork becomes crispy, about 5-7 minutes.

Flip one more time, pork side up, and spread Okonomiyaki sauce and mayo on the pancake and pork.

Sprinkle dried green seaweed, then dried bonito flakes over the pancake. Serve hot.