Roll out 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. Press with fork to make nice design.  Refrigerate until ready for use.
 

Mix sugar and flour. Layer rhubarb and sugar mixture in pie
pan. 

Place flour and brown sugar in food processor and process for 10 seconds.  Add chunks of butter and process for 10 - 20 seconds more.  If you don't have a food processor, mix all ingredients by hand until crumbly.

Gently distribute topping evenly over filled pie crust.

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 halfway through baking, to avoid excess browning.

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

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!