Buttermilk Rusks, South African

"This needs a little explanation. We South Africans are very partial to rusks with that first cup of morning coffee! It's what the US calls "double-baked": the end result with this recipe is a hard, chunky sweetish "rock" which you dunk in your coffee or tea to soften, then bite off. It doubles as a quick breakfast or an afternoon bite with tea and coffee. It's an all-purpose snack and most houses are never without a tin of them. There are all kinds of variations including health and muesli rusks. They date back to the time when people trekked with oxwagons into the interior, when they needed foods that would keep...."