You know, I really used to miss Ouma's Rusks too. Then I spent an ungodly amount on a box of them in London and I discovered that Ouma's rusks have been ruined! They're no longer those nice, irregularly shaped home-made-feeling rusks, but instead, square, regular, not-at-all-special rusks.
This is the quintessential South African food website for homesick South Africans.
I get all my recipes off Google -- even boerewors! Here are a few hits:
Recipezaar and
this South African forum.