Burek * 1 package dry yeast * 1/4 c lukewarm water * 1/4 tsp Sugar * 3 1/3 c all purpose flour * 1/2 tsp salt * 3/4 c lukewarm water * 1/2 melted butter Filling * 9 eggs (slightly beaten) * 1/2 lb crumbled feta Cheese * 3 TB melted butter