Mix the blueberries, sugar, flour, cinnamon, lemon zest, and lemon juice in a large bowl. Put in bottom pie crust. Dot with margarine pieces (I forgot to do this on Sunday). Place second crust on top and press together. I brush the top with a little soy milk before baking.
Score the pie on the top with 4 cuts (so steam can escape while cooking). Place the pie on the middle rack of the oven on top of tin foil to catch spills. Bake for 20 minutes at 425°.
Reduce heat to 350°F and bake for 30 to 40 minutes more or until juices are bubbling and have thickened. (After about 10 minutes at 350 I brush the crust with margarine.)