Uh…actually, you’re right. I have a box of tempura batter right here that doesn’t have any egg in it, and just calls for the addition of cold water. But when I hopped on Google to see if I could just make my own, every recipe I saw said egg, egg, egg, egg, and egg. (Or egg with SPAM, as the case may be.)
So tell me more about this “special low-gluten flour.” Does it have a Japanese name? What should I look for on my next trip to Little Tokyo?