Beat the eggs with the sugar, add the melted lard and yoghurt mixed with the ammonium bicarbonate and vanilla. Gradually add flour and knead a soft dough.
From the soft dough, make balls the size of a walnut and bake in a preheated 392°F (200 °C) oven until reddened. Stick them together in pairs using the marmalade.
Dissolve the confectionery dyes and dip one end of each biscuit in the red, then the other end in the yellow and then roll them in the sugar.
For the leaves you can use green marzipan. Or improvise and use buxus leaves, buttercream, cold glaze or even leaf shapes cut out from green paper.