grate potatoes and put in a collander and squeeze out extra moisture. Mix with diced onion salt, pepper and oil.
Working fast before the potatoes discolor, Place on sheet phyllo dough with short side to you (Covering rest with damp towel)Brush with melted butter and put a large hand full of potato mixture in center leaving a 1 inch margin around sidea and ends.
Roll until Burek is completely rolled and put on a lightly coated cookie sheet with seam side down. and brush with butter. complete the rest. cut slashes through the Burek's (6 for appetizers and 4 if part of dinner) and sprinkle with a little water.
bake at 450 degrees for20 to 25 minutes, brushing once more with butter half way through. serve hot