Grease 8 inches deep round cake pan, line base with paper and grease paper, beat butter, lemon rind and sugar until light and fluffy, add in 1 egg at a time, beat until combined.
Fold in sifted flour, spread mixture into prepared pan, bake on 180 degree for 20 minutes, sprinkle nuts evenly over cake, bake for another 30 minutes, remove cake, cool for 5 minutes, before turning onto wire rack.