Wash and dry feverfew leaves. Mix together flour and yeast in a bowl. Break the eggs into a container and beat them with a whisk, together with the salt and sugar. Pour in cold milk and mix together until it is well blended and then add to flour. Mix thoroughly with a whisk. Cut feverfew up finely (do not chop) and add to mixture. Cover with a tea towel and leave in a cool place for half an hour. Pour a generous amount of oil into an iron pan. Turn up flame to maximum heat so that oil boils quickly at 180°C. Using two spoons, place spoonfuls of the mixture into the boiling oil. When they are golden brown on all sides, remove and dry them on paper towels. Continue this procedure until all the mixture is used up, frying just a few “spoonfuls” at a time so as not to lower the temperature of the oil too much. Serve them dusted with powdered sugar.