Instructions

1. In a large saucepan, whisk cornstarch and sugar until no lumps remain.  Add blueberries, water, and lemon juice and stir gently to combine. 
2. Cook over medium heat, stirring frequently to prevent it from burning, until the mixture thickens and becomes translucent.  This will take about 10 minutes. 
3. Remove from heat.  Cool completely before filling the pie crust. (*very important - it will be impossible to do the lattice top as the pieces of crust will stick to the warm pie filling.)
4. Roll out prepared pie crust to about ⅛” thickness.  It should hang over the edge of your pie plate by at least an inch.  Pour cooled blueberry filling into the pie plate.  
5. Roll out the second prepared pie crust to ⅛” thickness.  Using a pizza cutter, pastry cutter, or knife, cut 12 strips that are the same width.  Lay 6 strips vertically, across the pie plate, spaced evenly.  The strips should be longer than the pie plate and drape over the edge on each side.  Fold back every other strip so that only the very top of each strip is still touching the edge of the pie plate.  Lay one of the 6 remaining strips perpendicular across the pie.  Unfold the 3 strips so that they now lay over the perpendicular strip that was just added.  Next fold the other 3 strips back and place another strip perpendicular across the pie.  Unfold the 3 strips so that they lay over the strip that was just added to the pie.  Continue until all the strips have been used and the pie has a beautiful woven top.
6. Roll the excess pie crust toward the center of the pie to make a nice edge.
7. Beat the egg and 1 Tablespoon of water together to make an egg wash.  Using a pastry brush, apply the egg wash to the top of the pie. Sprinkle with coarse sanding sugar.
8. Bake pie, uncovered, at 400℉ for 25 minutes.  Cover pie edges with foil or pie crust shield and reduce oven temp to 325℉.  Bake an additional 35-45 minutes or until lattice top begins to brown. 
9. Allow pie to cool for 3 hours at room temperature before service.  Store covered in the refrigerator or up to 5 days.