Gluten, Dairy, Egg Free Rhubarb Pie

I was recently challenged to harvest the vast amounts of rhubarb from our yard and create an allergen free pie. Somehow, to my own amazement, a very good dessert came out of it. Here's the recipe:
Ingredients:
One 8oz. package gluten free cinnamon cookies (we used Jo-Sef Brand)
2 1/2 cups minced fresh rhubarb
one 11 oz. jar strawberry preserves
1 or 1 1/4 cup sugar (more to taste)
1/2 teaspoon salt
Topping:
approx. 2 tablespoons shortening (whatever you like--butter, lard, oil)
1 tablespoon cinnamon
3 tablespoons brown sugar
2 tablespoons tapioca flour

Crush about 6 oz. or 3/4 of the box of cinnamon cookies into crumbs.
Spread these crumbs along the bottom of a pie tin or pie pan.
Mix together the minced rhubarb, strawberry preserves, sugar and salt.
Pour this mixture over the cookie crumb crust.
In a small stove top pot (cooking at low heat) combine shortening, brown sugar, tapioca flour and cinnamon. Let it melt and mix together, then sprinkle over the rhubarb filling evenly. It's ok if it doesn't coat completely, and add more sugar/cinnamon or flour to taste.

Cook in preheated oven at 425 F (uncovered) for 10 minutes.
Lower heat to 350 and bake an additional 40 minutes.
Let cool and serve with rice cream or ice cream.