In a large bowl, combine the eggs, water, soy sauce, and hondashi (if using). Mix well, then add the flour and baking powder, whisking until smooth.

Gently fold in the finely shredded cabbage and sliced scallions until well mixed.

Pour the neutral oil into a skillet and warm over medium heat. Test readiness with a drop of batter.

Add the cabbage mixture to the skillet, spreading it evenly. Cover and cook for about 4 to 5 minutes.

Carefully remove the skillet from heat, place a plate over the pan and invert the okonomiyaki onto the plate.

Slide the pancake back into the pan, browned-side up, and cover. Cook for another 4 minutes.

While cooking, whisk together the mayonnaise and Sriracha in a small bowl.

Transfer the cooked okonomiyaki to a serving plate. Drizzle with Sriracha-mayonnaise; garnish with scallions and nori.