Boil the kumara in a saucpan of water for 15 minutes. Meanwhile melt the butter gently in a saucepan then add the tahini and honey. Allow to cool. Place walnuts in a loaf tin and cook in the preheated oven for 10 minutes.
Sift the flour into a mixing bowl along with the baking powder and bi carb soda. Add in the sugar and cherries then roughly crush the cooled walnuts into the mix.
Purée the kumara then add the cinnamon, nutmeg, ginger and orange rind. Add a few drops of vanilla essence to the melted butter mix then add to the purée. Add the eggs.
Pour the purée into the dry mixture and then fold together just until mixed. Pour into the loaf tin and bake for 50 minutes to 1 hour until a knife comes out clean.
The Kumara is known in Australia as a sweet potato.