How to make
Heat the milk in a suitable container to boiling point. Add the vanilla (if using a pod, even better) and leave it as is for 15 min., to release its aroma, then leave it to cool. In the meantime, melt the butter.
Pour the egg whites in a deep bowl and beat them with a mixer into thick snow. In another bowl, beat the egg yolks with the sugar to a fluffy cream, then add the butter (needs to be at room temperature) and stir carefully.
To the yolk mixture, add the milk, grated lemon rind and stir. Gradually add in the flour and stir until homogeneous. Using a spatula, add the egg whites and stir carefully (the egg white mixture must NOT homogenize with the rest of it).
Butter and flour a cake form that's 9 1/2″ (24 cm) in diameter. Pour the mixture into it, smooth it out with a spatula on top and bake for 50 min. at 300°F (150 °C).
Leave the cake to cool for about an hour at room temperature, then put it in the fridge for 2 hours (this step is crucial because the 3 layers will form as the cake cools in the fridge). Sprinkle the cake with powdered sugar.
This recipe is from an Italian site. The cake is super tasty but I only had 2 layers form when I made it. Maybe I didn't cool it right, although I followed all the other steps listed.
