Roll a little more than half of the dough in a circle with a diameter of 12 inch
Place this on the buttered bottom of a pie dish and cover the sides
Roll the other part of the dough in a 10 inch circle, this will be the cover of the pie
Pre-heat the oven at 350 F (180 C)
Sprinkle 2/3 of the brown sugar on the pie bottom
Add the rhubarb mixture
Sprinkle the remainder of the dark sugar on the rhubarb mixture
Cover with the 10 inch dough circle, and push the dough together
Make short cuts with a sharp knife in various places of the cover, so that steam can escape when baking
Place the pie in the middle of a pre-heated oven at 350 F (180 C) for 1 h, checking the pie for color after 40 minutes
After taking the pie out of the oven, let it cool down on a rack