Grease and flour a 9" piepan and line with 1 crust (remove top sheet of waxed paper, place piepan upside down on dough, invert and carefully remove second sheet of waxed paper; this technique makes it easy to transfer dough to pan without stretching or tearing). Score the other dough circle into 1/2" strips and set aside.
Once the bottom crust has been filled, take the dough strips that were set aside for the top crust and layer them on at right angles. Start with the shortest strips; lay one strip across the pie vertically near the left edge. Then lay another short strip horizontally near the top edge. Continue, laying strips alternately vertically and horizontally, until you have a nice-looking lattice crust.