Martha Stewart Blueberry Lattice Pie

Directions

• Make the dough: Pulse 3 3/4 cups flour, 1 1/2 teaspoons kosher salt and 1 1/2 teaspoons sugar in a food processor. Pulse in 3 sticks of cold cubed butter until it looks like coarse meal. With the machine running, stream in 1/2 cup ice water just until the dough holds together. If it is crumbly, add up to 1/4 cup more, and never process past 30 seconds.
• Chill the dough: Turn the dough out and divide it into three equal pieces, then flatten each into a disk and wrap tightly in plastic. Refrigerate at least 1 hour, or freeze for up to 1 month.
• Preheat the oven: Heat the oven to 425°F with a rack in the center. Line a rimmed baking sheet with foil and set it on the rack to preheat.
• Mix the filling: Gently toss 3 pints blueberries, the zest of 1 lemon, 1 tablespoon lemon juice and 1/2 cup sugar in a medium bowl. Add 3 tablespoons cornstarch, 1/4 teaspoon kosher salt, 1/4 teaspoon cinnamon and 2 tablespoons cubed butter. The cornstarch coats the berries so the juices thicken as the pie bakes.
• Line the pie dish: Roll one dough disk on a floured surface into a 13-inch round and fit it into a 9-inch pie dish. Refrigerate it while you make the lattice.
• Cut the strips: Roll a second disk into an 11-inch square, trim the edges, then cut it into 10 strips, each 1 inch wide. Repeat with the third disk.
• Weave the lattice: On a parchment-lined unrimmed baking sheet, lay two touching strips diagonally across the center, then lay a single strip over them in the opposite direction. Keep weaving double and single strips, folding the doubles back as you place the singles, then freeze the sheet for about 30 minutes until the lattice is firm.
• Assemble the pie: Spoon the blueberry mixture into the dough-lined dish and brush the crust edges with the beaten egg. Lay the chilled lattice on top, press to seal, trim to a 1-inch overhang and tuck it under so it sits flush with the rim. Brush the lattice with more egg and sprinkle with sanding sugar.
• Bake the pie: Bake on the preheated baking sheet for 20 minutes, then drop the oven to 375°F. Keep baking 60 to 75 minutes more until the filling bubbles and the crust is evenly browned, tenting the edges with foil if they color too fast.
• Cool completely: Move the pie to a wire rack and let it cool completely before slicing. Martha notes this can take a long while, but that time lets the filling set so it doesn't run.