Beat the eggs with a whisk in a bowl. Add the sugar and vanilla sugar and beat until it melts.
Next add in the yoghurt with the extinguished baking soda in it, then the oil (can replace oil with 3 tbsp lard).
Add the sifted flour in stages - to obtain a medium soft and smooth dough. In the oven tray, laid out with baking paper, arrange balls of the dough, shaping them into walnuts.
I got 20 cookies total but you can make them smaller if you like.
Arrange them with at least 1/2″ (1 cm) space in between because they expand. Beat the egg well, then dip a brush in it and smear the cookies with it.
Sprinkle with sugar on top and put the tray in a preheated 356°F (180 °C) oven.
Bake to a nice brown color.