Preheat oven to 350°. Grease and flour a 10-in. fluted tube pan. In a large bowl, cream the butter, cream cheese and sugar until blended. Add eggs and egg white, one at a time, beating well after each addition. Beat in lemon zest and vanilla.
Toss blueberries with 2 tablespoons flour. In another bowl, mix the remaining flour with baking powder, baking soda and salt; add to creamed mixture alternately with yogurt, beating after each addition just until combined. Fold in blueberry mixture.
Transfer batter to prepared pan. Bake 55-60 minutes or until a toothpick inserted in center comes out clean. Cool in pan 10 minutes before removing to wire rack; cool completely.
In a small bowl, mix confectioners' sugar and lemon juice until smooth. Drizzle over cake.
Editor's Note: For easier removal of cake, use solid shortening when greasing a fluted or plain tube pan.