Dough: In a large bowl, mix the sour milk, olive oil and egg. Slowly add the flour and knead into a soft ball. Filling: In a medium sized bowl, chop the aromatic herbs, crush the cheese and mix together. Cut the dough in small squares/circles and roll out into thin phylllo sheets. Add a spoonful of filling in the center of each and close in a crescent pressing with a fork. Place on non stick paper and coat with egg yolk.