Roll out half of dough on lightly floured board and fit into 9" pie pan (I actually roll out the dough on a pastry cloth, gently set the pie pan upside down on top of it,then turn it right side up, and finally remove the cloth).  Press around the edges to evenly distribute the dough.  Refrigerate until ready for use.

Mix sugar and flour.  Layer rhubarb and sugar mixture in pie pan.  Dot with butter. 

Roll out the second half of dough on lightly floured board, just slightly larger than pie pan.  Place on top of filled crust (I roll out the dough on a pastry cloth, and gently turn the whole cloth onto the filled crust, thereby avoiding ripping the top crust when attempting to lift it from the board!).  Press top and bottom crust together at edges, tucking under any excess dough.  Press rim with fork.  Cut slits in top crust, and sprinkle with sugar.

Cover edge of pie with a strip of aluminum foil, securing with scotch tape if necessary.  Place large sheet of aluminum foil lightly over top of pie, to avoid excess browning. 

Bake at 400 degrees for 40 to 50 minutes, until filling begins to bubble through crust slits.

Cool and serve with vanilla ice cream.

This pie is very rich and sweet/sour, so it can make anywhere from 6 to 10 servings.

Note:  For vegan version, use soy margarine instead of butter, omit egg yolk in crust, and skip the ice cream!