Toss cabbage, fall vegetables, scallions and salt together. Toss mixture with flour so it coats everything, then stir in the eggs.
Heat a big skillet or griddle over medium high heat until a drop of water evaporates on contact. Add a thin layer of oil and heat for a few seconds.
Add 1/4 of the okonomiyake mixture to the skillet, pressing it out into a 1/2- to 3/4-inch pancake. Gently press the pancake down flat. Cook until the edges start to brown, about 3 minutes. 30 seconds to 1 minute later, flip the pancake with a large spatula. Cook on the other side until the edges brown, about another minute or two.
Slide onto a plate and keep warm in the oven while you cook the others.
To serve, drizzle with hoisin, sriracha, and mayo to taste and sprinkle with sesame seeds and scallions.