First, beat the eggs with the vanilla sugar until frothy. Then add the melted butter and the sweetened condensed milk and keep stirring. Sift baking powder with flour and fold in. Place in a springform pan that has been greased and dusted with flour. Bake in a preheated oven at approx. 180 ° C for 25 minutes until golden brown. If you like, you can decorate with powdered sugar or fruit.