All you will need is...
4 cups chopped rhubarb (I substituted 2 cups strawberries)
1 1/3 cup sugar
6 TBS flour
Two 9 inch pie crusts and of course a pie tin. ( maybe next time I'll get fancy and make the pie crust myself)
Start by heating your oven to 450°. Follow the directions on the pie crust packaging for the bottom of your pie, I had to cook the bottom crust for 10 minutes by its self. While the pie crust was cooking I chopped up my strawberries and rhubarb and mixed them together, and in a separate bowl whisk together the flour and sugar. Once the crust was done cooking and removed from the oven I put 1/4 of the sugar flour mixture on the bottom of the pie. Next I dumped the fruit mixture in and covered that with the remaining flour and sugar. Now cut the butter into little pieces and cover the flour and sugar mixture with it followed by the top pie crust. My edges came out horrible so I won't even get into how I did that but if you know how to make it look pretty power to you and please comment with your pointers!
(note: This recipe only makes one pie, I doubled up. See how pretty my crust was supposed to look?)
Finally put a couple of slits on the top of your pie crust and pop into a preheated 450° oven for ten minutes on the bottom rack. I placed my pie on a cookie sheet and I am so glad I did because there was a little bit of boil over. Cook at 450° for 10 minutes then lower your oven to 350 and cook for 40 to 45 additional minutes. Serve hot with ice cream or cold with coffee, either way it's delicious! Now you know why your grandpa loves rhubarb so much! As an afterthought had I decided to only use rhubarb and not add strawberries the pie still would have been delish. So have fun and experiment by adding your favorite fruit for another layer a flavor.