How to make
Beat the eggs with the sugar until whitened and add the margarine, yoghurt with the dissolved therein ammonium bicarbonate, orange zest and vanilla. Start adding flour until you get a medium soft dough. Knead it well and leave it in the refrigerator for 2 hours.
Shape small balls of dough and roll each on one side in a mixture of sugar and cinnamon. Arrange them on a tray with baking paper and bake them in a moderately heated oven until you get a pale pink color.
Optionally, stick them together with a jam of your choice and ground walnuts or peanut butter.