Preheat oven to 200ºC .
Mix everything but the rhubarb together, and then add the rhubarb at the end. Add filling to a 23 cm pie crust.
Bake at 200ºC or 15 minutes. Reduce heat to 350 and bake for another 25 minutes. Remove the pie, and sprinkle the crumb topping on top (see below for crumb topping recipe). Bake at 180ºC or another 15 minutes or until the topping is brown.
Modifications to the pie to suite taste. I find that the pie tastes plenty sweet enough with half cup of sugar, and I use "fat-free sour cream substitute" instead of real sour cream. Also, I like to use a bigger pie crust, and then make up the difference by adding as much rhubarb as will fit into the crust.
CRUMB TOPPING one third cup sugar (I use quarter cup) one third cup flour (I use half cup) half tsp salt quarter cup butter (softened) 1 Tbs cinnamon (I use more) Simply mix the ingredients together until crumbly.