- To make the batter: Mix the flour, water, dashi powder and baking powder together in a bowl to make a runny batter that is the same consistency as pancake batter. Cover and place in the fridge.
- To make okonomiyaki sauce: Heat the sugar, oyster sauce, tomato sauce and Worcestershire sauce in a small saucepan. Simmer gently then check the taste. If you prefer a tangier sauce, add more Worcestershire sauce. Set aside.
- Heat a BBQ hot plate or a large non-stick pan, add a dash of oil and spoon approximately ¼ cup of batter onto the hot plate and spread into a circle. Sprinkle some crispy bits onto the batter, then place a large handful of shredded cabbage on top. Place some of the shredded spring onions on top of the cabbage. For the last layer, place the pork belly on top and drizzle over some batter to hold it all together. With two spatulas, flip the okonomiyaki over so that the pork side is down.
- On a spare part of the hot plate or in another pan, drizzle some okonomiyaki sauce over a handful of soba noodles and stir fry it. Once the pork is cooked, use the spatulas to place the okonomiyaki pork side down on top of the fried noodles. Move this aside, then crack an egg onto the hot plate or pan. Move the okonomiyaki noodle side down onto the egg, cook for 1 min, then place the whole okonomiyaki onto a serving plate.
- Serve with the okonomiyaki sauce and Kewpie mayo.