Preheat the oven to 160C

In a bowl beat together the butter, 1/2 cup sugar and the zest. Then add in the egg yolks

One at a time and continue beating away. Flour, salt and the vanilla go in next

Finally lemon juice and milk. The batter will be runny... so don't freak out!

Take another large bowl, and beat the egg whites until soft peaks form. Add the remaining sugar (1/4 cup), and the cream of tartar and continue beating it until you get stiff peaks

Slowly mix the egg whites into the batter and mix well to combine

Pour this batter into a well greased baking dish

I then placed this dish into a large baking dish and filled it with boiling water until it reached

Halfway up the outside of the batter dish (hope that made sense haha)

Bake in the oven for about an hour. The top will brown a bit and the cake won't be very jiggly

Allow the cake to cool for the next hour before serving as it helps the cake to settle. I was SO impatient, but waited for the hour while I focused on some household chores  .. :) YAY!

I sprinkled it with powdered sugar and served.  It was warm, lemony and just lovely!