YOGURT CAKE WITH PISTACHIOS

This comes from Moro's cook book.
You need:

3 eggs, separated
70 gr sugar
one teaspoon vanilla extract
juice of 1 lemon
zest of 1 lemon
zest of half orange
350 gr yogurt
20 gr flour
a handful of shelled and chopped pistachios
Beat the egg yolks with the sugar until they become pale. Add the vanilla extract, yogurt, zests, lemon juice and flour and mix well. Wish up the egg whites and mix it with the yolks mixture.Put it all in a baking dish and then put the dish into a wider tin. Put the tin into a preheated oven at 180 degrees and add water to the tin until it comes halfway up the baking dish. Cook for 30-35 minutes (adding the pistachios for the last 10 minutes)  until brown. It will sink after you take it out but what counts is the taste. The smell is amazing and children cannot stop eating this.