In a small mixing bowl, cream butter and sugar. Beat in the egg, milk and vanilla. Combine the flour, baking powder and salt; stir into creamed mixture. Fold in blueberries.
Pour into three 4 inch fluted tube pans coated with nonstick cooking spray. Bake at 350* for 25 to 30 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.
For icing, in a small bowl, combine the confectioners' sugar, milk and lemon juice; drizzle over cakes. Garnish with additional blueberries if desired.
NOTE: If using frozen blueberries, do not thaw before adding to batter.