Last month I had a Marcel Proust-madeleine moment where a bite of a baked good—in my case, a rusk—brought back memories of a long ago event. Unlike Proust’s profound experience, where I ate this cookie was far more interesting than the memory itself. Chewing on a nut-flecked rusk while I stared out at four graceful impalas drinking from a water hole in South Africa’s Kruger National Park, I remembered that a decade ago I had written a syndicated article about twice-baked cookies and that that article had included rusks. Yeah, my memory wasn’t nearly as cerebral as Proust’s, either. Rusks have featured in South African cuisine since the 18th century, when Dutch farmers or boers living in South Africa looked for ways to make bread last longer. By baking loaves of dough twice, they learned that they could remove all the moisture from the loaves. This gave their bread or rusks an almost endless shelf life. In times when food was scarce and shopping for supplies involved traveling long distances over hot, barren landscapes, they …