1/2 teaspoon sesame seeds
1/3 cup mayonnaise
1 tablespoon Sriracha
2 tablespoons hoisin
5 ounces very thinly sliced green cabbage (about 2 cups)
3 ounces very thinly sliced baby bok choy (about 1 cup)
1/2 teaspoon grated fresh ginger
4 green onions, thinly sliced
3/4 teaspoon coarse kosher salt
1 tablespoon white rice flour
1 egg, beaten
2 teaspoons canola oil
Optional: 1 egg, for topping
Place sesame seeds in No. 6 Skillet and set over medium-low heat. Toast until golden brown, stirring constantly, about 5 minutes. Remove from skillet and reserve.
In a small bowl, stir together mayonnaise, Sriracha, and hoisin. Reserve.
In a large bowl, combine cabbage, bok choy, ginger, and the light part of the green onions (reserve the dark tops for garnish). Sprinkle rice flour over the top and season with salt. Add egg and stir until evenly combined.
Heat canola oil in the same No. 6 Skillet over medium heat until shimmering. Add cabbage mixture, pressing gently on the top and sides with a spatula to shape into a pancake. Cook over medium to medium-low heat until a golden crust forms on the bottom and edges, about 5-7 minutes.
To flip, carefully place a large plate over the top of the skillet and quickly invert. Slide the pancake back into skillet, browned-side facing up. Continue to cook until tender throughout and golden on the bottom, about 5-7 minutes longer.
Slide okonomiyaki onto a serving plate.
Optional: Gently crack an egg into the same No. 6 Skillet and cook over medium-low heat until whites are set and yolk is slightly thickened but still runny, about 3 minutes. Place on top of the okonomiyaki.
Drizzle with hoisin-mayonnaise and sprinkle with toasted sesame seeds and reserved green onion tops.