Preheat the oven at 180 degree Celsius.
Separate the egg white from the egg yellow in different bowls.
Add the warm water in the bowl of egg yellows.
Add the sugar, and vanilla sugar in the egg yellow and water and whip it to a creamy consistence.
Whip the egg white to a hard consistence.
Mix the egg whites and the egg yellow mixtures together very gently with a spatula.
Pour the flour, the starch and the baking powder though a strainer in the egg mixture, and mix gently with the spatula.
Butter the lamb baking form, put a lot of butter in the ear of the lamb.
If you have a form that is divide in 2 pieces, put them together tightly.
Put the form upside down, and pour the dough in the form.
Place the form in the middle of the oven for 40 minutes.
Take out the form and let it cool down in room temperature.
Take out the cake from the form gently.
Put it on a serving plate and sprinkle icing sugar on the cake.
Put a ribbon around the neck of the lamb as decoration.