Soak the raisins in warm water for about 15 minutes.
Pour the milk in a standup mixer bowl. Sprinkle the yeast over the lukewarm milk and give it a few minutes to activate. Add the flour, sugar, salt and half the beaten egg. Equip the mixer with a dough hook and run at its lowest speed. Let kneed until well mixed.
Add the butter and grated lemon peel and kneed until the gluten is well-developed, about 5 minutes.
Dry the raisins in kitchen paper. Sprinkle them with flower to help them stick to the dough. Roll out the dough and fold in the raisins, about 1/2 each time. Cover with plastic and let rise until doubled in size, about 1 hour.
Divide the dough in 12 pieces and roll small balls from them. Space them on a baking sheet and cover brush them with the remainder of the egg mixture. Cover with plastic, and let rise until doubled in size, about one hour.
Preheat the oven to 430 °F (210 °C). Bake for until browned, about 15 minutes. Let cool. Bag them in a plastic bag.