20 ounces blueberries, approximately 4 cups  | 4 ounces sugar, approximately 1/2 cup |
1/8 teaspoon kosher salt  | 1 1/4 ounces tapioca flour, approximately 5 tablespoons |
1 tablespoon fresh orange juice  | 1 teaspoon orange zest |
2 (9-inch) homemade or store-bought pie doughs  | 1 egg yolk whisked with 1 teaspoon water |