Rhubarb, strawberry, and apple pie

From the title of this post, you already know that changes had to be made to the original plan of a strawberry-rhubarb marriage - a third pie-appropriate filling needed to be added. Turns out the half-share I have in the CSA didn't give me quite enough fruit for the pie - a little under 2 cups of strawberries, and 3 or so cups of rhubarb, when all was washed and cut up. In the midst of baking the pie, what was I to do?

Rather than scrap the idea entirely (I had managed to make a half-decent looking bottom pie crust, so had beaten my expected nemesis), I considered my options. Obviously, more had to go in the pie, or the proportions of sugar and spices would be off, and the volume of the pie would be sad-looking. This left me with two options in the refrigerator: blueberries (yes, I realize they're far from local this time of year, but I couldn't resist them for my morning cereal) or a Granny Smith apple. Blueberries, no matter what their provenance, tasted wrong to me in my head. Apples, on the other hand, seemed to go well with the spices (cinnamon, ginger, and nutmeg), and the texture of the fruits already in the mix.

I began with a base recipe from Anna Olson's cookbook Sugar: Simple Sweets and Decadent Desserts, added the apple, and also took the liberty of substituting arrowroot powder for the cornstarch. This is because Baking Illustrated (the baking cookbook put out by the same people who write Cook's Illustrated magazine and their assorted cookbooks) had mentioned that tasters enjoyed the thickening power of root-based thickeners over cornstarch, but tapioca interacted with the rhubarb to give the pie a gummy texture.

Now, the difficulty is that I cannot sample this pie until tomorrow night. I'm bringing it to our friends' home in Ottawa, and the hard thing about bringing pies anywhere (and cakes, too, for that matter), is that it seems impolite to have already eaten a piece. Until I taste it, the recipe and a picture of the finished product will have to satisfy your curiosity (and mine) about how it tastes.

Rhubarb, strawberry, & apple pie
adapted from Sugar: Simple Sweets and Decadent Desserts

Crust
1 1/4 cups all-purpose flour
1/4 tsp salt
1/4 cup unsalted butter, chilled
1/4 cup vegetable shortening
1 Tbsp lemon juice
3 - 5 Tbsp cold water

Fruit filling
3 cups chopped fresh rhubarb
2 cups hulled and sliced strawberries
1 peeled and chopped Granny Smith apple
1 cup sugar
2 Tbsp arrowroot powder
1/2 tsp cinnamon
1/4 tsp ground ginger
dash of salt

Crumble topping
2/3 cup all-purpose flour
1/2 cup sugar
1/4 tsp freshly-ground nutmeg
dash of salt
1/4 cup unsalted butter, melted

For crust, mix flour with salt. Cut in butter and shortening with pastry cutter until mixture is a roughly even crumbly texture. Add lemon juice and water until dough comes together enough to shape into disc. Wrap disc in plastic wrap and chill for 30 minutes.

Preheat oven to 400 degrees C. Roll out dough on lightly floured surface to fit a 9-inch pie pan. Line pie pan with pastry, and trim and crimp edges. Chill while preparing fruit for filling.

For the fruit filling, toss the rhubarb, strawberries, and apple with sugar, arrowroot powder, spice, and salt to coat evenly. Fill pie shell with fruit.

For the crumble topping, mix flour, sugar, nutmeg and salt in small bowl. Mix in melted butter until crumbly (this is easiest with your hands), and spread over fruit. Bake pie on a foil-lined baking tray (to facilitate clean-up) in the 400 degree oven for 20 minutes. Turn the temperature down to 350 degrees for the 40 more minutes, or until the fruit is bubbling.