Preheat the oven to 160°C (fan forced). If using a conventional oven, preheat to 180°C.
Grease a cake tin and line the base of the tin with baking paper.
Using an electric mixer/beater, beat the softened butter, sugar and zest till creamy and fluffy.
Then add the eggs one at a time, beating after each one to incorporate.
Sift the flour into the beaten mixture and add the juice of ½ lemon. Beat for a few seconds to incorporate (just a few seconds!). Taste and add more lemon juice if necessary.
And finally, add the milk and beat for a few more seconds till incorporated.
Pour the cake batter into the tin and tap gently to settle the batter evenly in the tin.
Bake for 40 minutes until golden. Make sure you check the cake after 30 minutes. Insert a skewer to check of the cake has cooked through and then bake more if necessary. If you find that the top of the cake is browning faster but not cooked inside, then reduce the temperature and bake further.
Stand in the tin for 5 minutes and turn onto a wire rack or cake stand to cool further.
Serve warm dusted with icing sugar or cool with buttercream icing like I did.
To prepare the buttercream:
Sift the sugar to ensure there are no lumps.
Using a hand/electric mixer, beat the butter till pale and fluffy. This will take at least 5-6 minutes or more by an electric mixer so be patient and let the mixer do its work.
Add ½ cup sugar, first mix on low speed and then on high till the sugar is fully incorporated. Continue until all the sugar has been added and mixed thoroughly with the butter.
Then add the vanilla extract; beat further till incorporated.
Add 1 tbsp of milk to fluff up the mixture. The texture of the cream is a personal choice so if you prefer a thick cream, then add just a tbsp but if you prefer a softer and more wet cream, then you can add more milk.
The quantities mentioned yield more buttercream than necessary. Either you can spread a thicker layer on the cake or hand over the bowl to your little one to lick!