In a bowl add the sifted flour with dry mother yeast. Then make a well in the centre and pour sugar, salt, lemon zest, eggs and warm butter. Combine all the ingredients with a fork and add warm milk little by little.
Knead the dough on a floured pastry board for 10 minutes at least, stretching it out with hands, roll it up and beat it on the table until the liquid will be assimilated. Put the dough into the floured bowl and let it rise until it doubles in size (an hour and half or so).
To fill, whip the butter with sugar (butter cream). Pour the dough and roll out until you have a rectangular phyllo dough (35x50 cm or so); then spread the butter cream and roll up the phyllo dough on the long side. Cut the roll in 12 parts and lay them down on a buttered (or lined with baking paper) baking tray.
Let it rise in a warm place for 20 minutes or so; bake in preheated oven to: electric oven 200-220°C, 190-210 °C in fan-assisted oven, 210-230°C gas oven, and bake for 20-30 minutes or so.