I’d never thought of the word, smidgen, as being anything but genuine, but another blogger found out only recently that it was in the dictionaries, and even acceptable by spellcheckers. (Incidentally, blogger itself isn’t acceptable according to the program I’m using here, and spellcheckers isn't accepted by Blogger.)
This blogger uses it in the cooking sense: putting in a smidgen of flour, or salt, or whatever. I’ve probably used it more in the expression: Just a smidgen, as when someone asks me how much sugar I want in my tea, or do I want some more hair cut off, or whether something is too long.
Having discussed smidgen, we now discover that there is a word, smidge, as well. Both may derive from the Scots word, smitch, which means a very small amount, or an insignificant person.
Well, next time I’m feeling particularly abashed, I may describe myself as a smitch.