Sift the baking soda, cream of tartar and 1 cup of flour together (repeat 3 times).
Sift all the dry ingredients together. If you are using aniseed, add it too and mix well.
Grate the butter into the mixture and rub (to mix) through with fingers.
Beat the eggs, add the buttermilk, mix and then add to flour mixture. Mix together so that mixture is little runny, but still can be kneed. Kneed lightly until all ingredients are mixed well.
Make little balls (slightly bigger than a golfball) with mixture and place them (touching) into a greased breadpan.
Bake for 25 - 30 minutes in the oven at a temperature of 400 °F.
When your rusks have cooled slightly, break (or cut) them into pieces and dry overnight in a cool oven by placing the rusks directly on the oven grills. (Set the oven on "Warm" only and keep the oven door slightly open by wedging a teaspoon into the door at the top.)