preheat oven to 350F/180C

in very large bowl, sift all the dry ingredients together

in a small pot, melt the butter and the sugar

Add the butter sugar mix and the buttermilk to the dry ingredients and combine

Shape into balls and pack into a lined or greased baking tray

Remove and turn the oven down to 100F/50C

Break the rusks up into chunks and place directly on the oven rack or a wire rack and leave overnight to dry out