Beat butter and sugar till creamy and fluffy.
Add eggs one by one, beating well between each addition.
Sieve flour and baking powder, fold into the mixture and also add the lemon juice and rind.
Line a baking tray with parchment paper all over and pour mixture inside.
Bake on preheated oven (10 mins) for about 40 mins or until the cake is done.
Remove the cake from oven and pour the frosting on top.
Leave it to cool down before cutting to shapes you prefer.