The best blueberry pie we ever made

I came up with the recipe for the filling--I was inspired by the article in the July/Aug. 2008 issue of Cook's Illustrated to add a grated apple to take advantage of the apple's pectin for thickening the filling. So I modified my usual recipe to incorporate the grated apple, and it's the best blueberry pie we've ever had! Not only does the apple enhance the texture, but it adds a fantastic tartness behind the sweet blueberries. I also made the crust, and Paul did all the rolling, assembling (and photography).

Blueberry pie

Pastry for double crust

For filling, mix all together:
6 c. frozen blueberries
3/4 c. agave syrup (or honey, or rice syrup, or sugar)
1 granny smith apple, peeled and grated on the large holes of a grater
Grated zest of one lemon (1/2 to 1 tsp. or so)
2 tsp. lemon juice
2 tbsp. instant tapioca
1/4 tsp. cinnamon (or nutmeg)
Dash of salt

Bake at 400F for ca. 50 min., until crust is golden and filling bubbly.