We mix the sugar with the butter and when the sugar melts, we add the yolks one by one. We dissolve the ammonia in the milk and we add it to our mixture. We slowly add the flour sifted and then we add the vanillin. We knead until we have a little dough that is fluffy and does not stick. We are creating boats, braids and whatever we like. We spread the cookies with an egg and we bake at 180 ° C for 20 minutes.