In a small 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-in. fluted tube pans coated with cooking spray. Bake at 350° for 25-30 minutes or until a toothpick inserted in 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 berries if desired.
If using frozen blueberries, use without thawing to avoid discoloring the batter.