1) In a large bowl, mix the the flour, salt, pepper and vinegar well with your finger.
2) Add 2 glasses of water and make a dough.
3) Crush the feta cheese.
4) Divide the dough into smaller portions and, on a floured surface, flatten a piece of the dough.
5) Add some cheese and wrap the dough all around it. Flatten with a rolling pin. Repeat till all the dough and cheese has been used.
6) Add oil to a pan and add one of the prepared cheese dough pieces.
7) Fry on both sides till browned and cooked. Repeat with all the others.