I haven’t made those yet. But in my experience with deep-fried stuff, keep the batter recipe as simple as possible - you want to taste the main ingredient. I was first going to post my Joy of Cooking recipe, which actually calls for separating the egg(s) and beating and folding in the whites - but ‘ain’t nobody got time for that!’, and I don’t think it really makes things better, unless you’re going to serve them all immediately; so in recipes like that, I often just mix the whole egg in.
And I would just dust them in powdered sugar, at least the first time you make them ;-)
-JT
I like the idea of cinnamon sugar for apples, even better than powdered sugar. Both will end on the floor though, make before mopping day...