Slice the lemons and combine in a large bowl with the 2 cups sugar. Let stand for at least 4 hours, preferably overnight.
Add the beaten eggs and mix well. Pour into an unbaked 9 inch piecrust and cover with a top crust.
Brush the top with milk and sprinkle granulated sugar on top.
Bake at 450 degrees F (230 degrees C) for 15 minutes, then reduce heat to 375 degrees F (190 degrees C) and bake for an additional 20 to 25 minutes, or until a knife inserted into the pie comes out clean.