For Pastry: Place flour, vinegar, and salt, in food processor. Cover and pulse until combined. Add cold butter and 1 egg yolk; cover and pulse until mixture resembles pea-size pieces. Add ¼ cup cold water to food processor; cover and pulse until combined. Slowly add 1 tablespoon at a time of ¼ cup ice water, using just enough water until dough holds together. Shape dough into disk; wrap in plastic wrap. Refrigerate 1 hour.

For Blueberry Filling: Combine 1½ cups blueberries and granulated sugar in small saucepan. Cook over medium heat 4 to 5 minutes or until most of the blueberries burst, stirring frequently. Stir together corn starch and remaining 2 tablespoons cold water in small bowl; add to blueberry mixture. Cook and stir 1 to 2 minutes or until thickened. Stir in remaining ½ cup blueberries. Remove from heat; cool completely.

Place oven rack in lower third of oven; preheat to 425°. Let pastry dough stand at room temperature 5 minutes or until soft enough to roll out. Meanwhile, for cream cheese filling, stir together cream cheese, remaining 1 egg yolk, 1 teaspoon lemon zest, and 1 tablespoon lemon juice in medium bowl until smooth.

Roll out pastry dough to ⅓-inch circle on lightly floured surface. Transfer to large baking sheet.

Spread cream cheese filling on top of pastry leaving a 2-inch border. Spread with blueberry filling on top of cream cheese layer. Fold edges of pastry over filling, pleating as necessary; leave center open.

Beat 1 egg white in small bowl with fork; brush over pastry. Reserve remaining egg white for another use. Sprinkle pastry with sanding sugar, if desired. Bake 25 to 30 minutes or until crust is golden. Transfer galette on baking sheet to wire rack; cool completely.

For icing, whisk together powdered sugar and enough remaining 2 to 3 tablespoons lemon juice in small bowl to make drizzling consistency. Drizzle icing over galette; sprinkle with remaining ½ teaspoon lemon zest.