I finally admit after eating 18 takoyaki(sakeyaki since it was salmon) for lunch I'm starting to get a bit sick of them. I've found the recipes online have been pretty good. But this is the one I use for my takoyaki machine(makes 18).
It's as simple as 1,2,3. 1 egg, 200ml of plain flour (i actually use around 180ml plain flour and 1 tbs self raising to make them puff more), 300ml of dashi (1 tsp instant dashi ganules made up to 300ml). Add a pinch of salt. You should end up with about 2 cups of batter.
For the filling I put in whatever I can find.I know that's not authentic but who can be bothered making tempura bits. I still haven't made or bought takoyaki sauce and have been using hoisin sauce instead, it's quite different but better than just plain mayo. I think I might give takoyaki a break now.