01 - Combine the chicken pieces with soy sauce, sake (if using), and grated ginger in a bowl. Let marinate for 10 minutes to absorb flavors.
02 - In a large bowl, whisk together the flour, baking powder, and salt until evenly combined.
03 - Beat the eggs in a separate bowl, then add the dashi stock (or water) and mayonnaise. Mix until smooth and fully incorporated.
04 - Pour the wet mixture into the dry ingredients and stir until just combined. Do not overmix; small lumps are acceptable.
05 - Fold in the shredded cabbage, spring onions, and grated carrot until evenly distributed throughout the batter.
06 - Heat a large non-stick skillet or griddle over medium heat and add a small amount of oil to prevent sticking.
07 - Add the marinated chicken pieces and cook for 2-3 minutes until lightly browned but not fully cooked through.
08 - Shape about one-quarter of the batter mixture into a round pancake approximately 3/4 inch thick in the pan, pressing chicken pieces evenly into each pancake.
09 - Cook for 4-5 minutes per side, pressing gently with a spatula to compact, until golden brown and cooked through. Repeat with remaining batter and chicken.
10 - Transfer to plates. Drizzle generously with okonomiyaki sauce and Japanese mayonnaise. Sprinkle with aonori and katsuobushi, and add pickled ginger if desired. Serve immediately.