Divide the dough into 2 equal pieces. Roll one piece into a 10" square on a floured surface, then cut into four 5" squares.
Scoop about ½cup of filling into the center of each square. Pull dough edges up and around the filling and pinch to close. Place them seam side down on the prepared baking sheet.
Repeat with the remaining dough. Brush knishes with oil and sprinkle with coarse salt (if desired). Bake for 30~40 minutes or until golden brown.