To prepare the jackfruit, pour jackfruit in a colander over the sink. Rinse in cold water and drain. Press to squeeze out all excess liquid.
Using your fingers, shred the jackfruit. Place shredded jackfruit in a bowl along with the mirin, soy sauce, sesame oil, ginger and garlic. Toss and mix well.
Heat a small cast iron pan on high. Add the marinated jackfruit and pan-fry on high heat for 5 minutes, tossing constantly. Remove from heat when starting to char and cool.
To prepare the Okonomiyaki, add flour, zucchini, cabbage, salt, miso paste, baking powder, spring onion and water to a bowl. Mix well. Add the egg and cooled jackfruit. Mix gently until just combined.
Heat a tablespoon of oil in a frying pan on medium heat so that it covers the whole surface. Spoon a cup of the okonomiyaki batter (quarter of total batter) in the middle of the pan in the shape of a round pancake about 6 inches in diameter and 1/2 inch in thickness. Cook for 5-6 minutes until golden. Gently flip over and cook the other side for 5-6 minutes. Reduce heat to medium-low and cook both sides again for 3-5 minutes until cooked through the middle. (A longer cook over lower heat will ensure that the okonomiyaki is not raw in the middle but completely cooked through. Also, remember not to press down on the pancake will cooking as this prevents it from rising and acquiring a fluffy interior)
To serve, place the jackfruit okonomiyaki on a plate. Squeeze mayonnaise in a zig zag pattern on the okonomiyaki. Follow this by squeezing barbecue sauce in the same pattern. Sprinkle with nori flakes (seaweed), sesame seeds and Sichimi Togarashi (Japanese spice mixture). Serve with Sriracha and salad greens.