I've never actually made latkes for one. But this is how I usually make them.
1 box potato latke/pancake mix (follow directions in preparing the batter)
add grated potato for texture - either fresh grated or frozen
(optional - chopped onion for added flavor)
drop spoonfuls into pan with hot oil and cook until golden brown
I suppose you could mix together an egg, grated potato, onion, salt, pepper, and a bit of flour then cook in oil. I'm not one for really measuring ingrediants when making latkes. I just mix stuff together until it looks like the right consistency.