Cake: Preheat oven to 180 degrees C. Grease and flour a 23cm square tin. Combine the flour, baking powder, salt, cinnamon and orange rind. Set aside.
In a large bowl, cream together the butter and 3/4 cup sugar until light and fluffy. Beat in the eggs one at a time. Beat in the flour mixture alternately with the milk, mixing just until incorporated. Stir in the walnuts.
Pour batter into prepared tin and bake for 40 minutes, or until a toothpick inserted into the centre of the cake comes out clean. Allow to cool for 15 minutes, then cut into diamond shapes and pour the honey syrup over the cake.
Honey Syrup: In a small saucepan, bring honey, sugar and water to a simmer and cook for 5 minutes. Stir in lemon juice, bring to a boil and cook for 2 minutes until thickened.