This is my approximation and adaptation of what I observed during the three times (in three days) I went to the Okonomiyaki theme park in Hiroshima. It's definitely not authentic, nor quick or easy to make, but definitely worth it. This combination of ingredients is my personal favorite but nearly everything is optional and/or adjustable; "okonomiyaki" in fact translates as "what-you-like grill".
Note: Asian food stores have seaweed flakes, and we get the ones pictured below at Costco. In a pinch you can use seaweed wrappers made for sushi rolls by tearing them into very small bits, but the seasoning that comes on the flakes is extra tasty.
Okonomi sauce can be found in Japanese stores or some general Asian stores. I usually use a simple substitute, which I in fact prefer due to having no fishy taste, although that makes it inauthentic. (Pssh; authenticity for authenticities sake is for foodies.) That substitute merely consists of the following three ingredients mixed together:
Rice paper sheets are the easiest way I've figured out to create a starchy layer while minimizing the risk of tearing and burning. They are sold as wrappers for spring rolls, and they get soft and sticky as soon as they contact hot water or steam. If you prefer to use a more traditional crepe-like layer, you can do that by mixing approximately 1/4 cup of flour with enough water to create a thin slurry the consistency of pancake mix.
Pour this into a hot frying pan and tilt the pan around until it spreads into a circle covering most of the bottom of the pan. Let this "crepe" cook briefly until it can be flipped. Leave on the second side until it's cooked through, and then remove from heat. Set the crepe to the side on a plate, and use in place of the rice sheet in the preparation instructions below.
I don't have nearly the mad skills that it takes to make authentic okonomiyaki, so I'll spell out the hacks I've come up for this recipe as they come up. You can make it work with a single frying pan, but having two (or more) helps with assembly.
I use frozen miniature shrimp and scallops that are pre-cooked but you can of course use fresh ingredients if you prefer. Mix these with the cabbage. Fry with a bit of vegetable oil in the first frying pan, mixing occasionally to prevent burning, until the cabbage is cooked through and the excess water has boiled off (or simply drain it if there's too much). Set to the side on a plate.
Arrange the boiled noodles into the form of a pancake and fry with a bit of vegetable oil in the second frying pan. When they start to get crispy on one side, flip and let them cook on the other side. Then remove from heat and set to the side, leaving them in the frying pan.
In a cup or bowl, mix up the raw egg/s with a couple tablespoons of water. Oil the first frying pan and pour in the egg mix, letting it spread out into a large circle. Let this cook until solid, popping bubbles as they form so it stays flat. When you can, flip it over and let it cook through. Set this egg pancake to the side on a plate.
Now oil the first frying pan again. Make sure the entire surface is oily; I use nonstick spray to accomplish this without using gobs of oil. On very low heat, put a rice paper sheet in the pan. Spread out the cabbage and seafood mixture across the rice paper, before it softens too much. If the cabbage is still hot, the rice sheet will soften almost immediately underneath. Then, spread pork fu on top of the cabbage mixture. Turn the heat off when the rice sheet is entirely soft.
Now, carefully flip the noodle pancake from the 2nd pan on top of the pork fu.
Finally, put the egg layer on top.
Now, use a plate that is slightly smaller than the frying pan with everything in it and put it, upsidedown, on top of the egg layer. Carefully flip the plate, okienomiyaki, and frying pan over so the plate is now right side up. Very slowly lift off the frying pan, unsticking the rice paper as necessary without letting the whole thing fall apart.
Spread the okonomi sauce or substitute on the rice paper top. Sprinkle on the seaweed flakes, crunchy deep fried onions, and green onion. Enjoy!