Preheat your oven to 160 C. Grease and flour a loaf pan (8x 5x3).
Whisk together the flour, baking powder and salt.
Using your mixer, beat the butter until smooth.
Add sugar, lemon zest and beat until light and fluffy (5 -6 mins)
Beat in the eggs (one by one) for a couple of minutes until well incorporated.
Alternately add the flour mixture in 3 additions and butter milk in two, starting and ending with the flour ( 1/3 of flour - 1/2 of buttermilk -1/3 of flour- 1/2 of buttermilk - 1/3 of flour).
Pour into prepared pan and smooth the top. Bake at 160 C for 45-50 minutes. A toothpick inserted in the centre should come out with few moist crumbs.You ll see browning of sides and top.
Cool in pan for about 10 minutes.
Meanwhile, mix the lemon juice and icing sugar to make the syrup.
Invert the cake onto cooling rack (right side up) and brush with syrup.
Now just wait until cool!