In a large, non-reactive bowl, whip the egg whites into foam. Set aside.
In a large mixing bowl, sift together flour, baking powder, salt, sugar.
Stir in dashi, sesame oil, chopped pickled chanterelles, scallion greens, egg yolks, mix thoroughly.
Gently fold in whipped egg whites - just enough to incorporate.
Preheat a skillet or griddle with a tablespoon of vegetable oil (if you have a griddle, it makes these a lot easier to make as you can do more than one at a time).
Place a fairly large handful of cabbage (see note) and ~3/4 cup batter in the center of the skillet/griddle over medium heat and flatten a little with a spatula (see note on thickness below).
Lay a few strips of smoked salmon on top of the okonomiyaki, then cover the pan (or put a pot lid over the individual okonomiyaki if you're using a griddle). Cook for about 3-4 minutes.
Flip and cook uncovered for an additional 2-3 minutes. Cool slightly, then add okonomiyaki sauce, mayo, and any other desired toppings.
Repeat steps 5-8 above with remaining batter, cabbage, and toppings. Best served immediately, as each individual pancake is ready.