Seconding the suggestion of a sweet matzo brei! For what it's worth, I didn't like matzo as a kid and now I enjoy it. You're absolutely right that the egg and onion is the best.
But children ARE picky. I played along growing up during Pesach because I thought the matzo was supposed to help me understand the suffering of the Exodus. I'd be more concerned if she didn't like latkes. On the other hand, all the more reason to make sufganiyot during Chanukah...
Oh, and my aunt used a piece of chocolate covered matzo for the afikomen while her children were finicky. She might find that more appealing.