Put the Fioretto cornflour, the sifted flour type 00, the pinch of salt, the vanilla flavouring or the seeds of half a vanilla bean and the granulated sugar in a bowl. With a wooden spoon, stir together all the dry ingredient then add the softened butter cut into pieces and grate the zest of a lemon into the mixture. Blend thoroughly to mix all the ingredients. Add the egg and the yolk and incorporate them well into the mixture, stir with a wooden spoon to obtain a creamy, soft and homogeneous mixture. Put the dough into a piping bag fitted with a star-shaped nozzle. Butter a baking tray on the sides and in the centre and line it with baking paper. Squeeze the dough directly onto it from the piping bag, forming small ring-shaped biscuits. Bake in a static oven at 180° for 15/20 minutes, until the biscuits are golden brown.