Fresh Plum-Ginger Pie with Whole-Wheat Lattice-Top Crust | America's Test Kitchen

Ingredients

• 20 tablespoons (2½ sticks) unsalted butter , chilled, divided
• 1 1/2 cups (8¼ ounces/234 grams) whole-wheat flour
• 2 tablespoons sugar
• 1 teaspoon table salt
• 1 cup (5 ounces/142 grams) all-purpose flour
• 1/2 cup ice water , divided
• 3/4 cup (5¼ ounces/149 grams) sugar
• 3 tablespoons cornstarch
• 2 teaspoons grated lemon zest plus 1 tablespoon juice
• 1 teaspoon grated fresh ginger
• 1/4 teaspoon ground ginger
• 1/4 teaspoon table salt
• 2 1/2 pounds (1134 grams) plums , pitted and cut into ¼-inch-thick wedges
• 1 large egg , lightly beaten with 1 tablespoon water