Rose Levy Beranbaum's Fresh Blueberry Pie

INGREDIENTS

• 1 1/3 cup + 4 tablespoon pastry flour or 1 1/3 cups (dip and sweep method) bleached all-purpose flour
• 4 cups blueberries, rinsed and dried
• 2 teaspoons lemon juice
• 1/4 teaspoon salt
• 2 tablespoons cornstarch
• 2 1/2 to 3 1/2 tablespoons ice water
• 1 1/2 cup whipped cream (optional)
• Pinch of salt
• 1/8 teaspoon non-aluminum baking powder (if not using, double the salt)
• 1 1/2 teaspoon cider vinegar (optional)
• 1 tablespoon egg white, lightly beaten (optional)
• 1/2 liquid cup and two tablespoons water, divided
• 8 tablespoons unsalted butter, cold
• 1/2 cup sugar