Sieve the flour and baking powder together and set aside.
Cream the butter and sugar together. Seperate the yolks of eggs and add one at a time.
Whisk white till very stiff. Fold in a little flour, and a little white of egg to the mixture alternately until all is lightly blended.
Add milk, vanilla, powdered cardamoms and grated lime rind.
Bake in a moderate oven (350 F) for about 30 minutes. Test before removing from oven.