Lattice-Top Blackberry Pie

Ingredients

• 1.8 lb blackberries 
• 0.3 cup cornstarch 
• 1  egg whites lightly beaten
• 1 tablespoon granulated sugar (coarse)
• 2 tablespoons juice of lemon fresh
• 8 servings pastry crust 
• 1 tablespoon cooking tapioca 
• 2 tablespoons butter unsalted melted
• 2 tablespoons water 

Equipment

• frying pan
• baking sheet
• oven
• knife
• aluminum foil

Directions

1. Make pastry dough.
2. Place a baking sheet in lower third of oven and preheat to 400°F.
3. Toss together berries, granulated sugar to taste, cornstarch, butter, lemon juice, water, and tapioca.
4. Let stand, tossing occasionally, 20 minutes.
5. Roll out 1 piece of dough into a 14-inch round and fit into a 9-inch pie plate (4-cup capacity). Trim edge, leaving a 1/2-inch overhang. Chill shell while rolling out top.
6. Roll out remaining piece of dough into a roughly 16- by 11-inch rectangle.
7. Cut crosswise into 11 (1 1/4-inch-wide) strips with a fluted pastry wheel or a knife.
8. Stir berry mixture, then spoon evenly into shell. Arrange strips in a tight lattice pattern on top of filling and trim strips close to edge of pan.
9. Roll up and crimp edge.
10. Brush top and edge with egg white and sprinkle all over with sugar.
11. Bake on hot baking sheet until crust is golden brown and filling is bubbling, 1 hour to 1 hour and 10 minutes. (Check pie after 45 minutes: If edge of crust is browning too quickly, cover edge with foil or a pie crust shield and continue baking.) Cool completely on a rack before serving.