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-in. fluted tube pans coated with cooking spray. Bake at 350° for 25-30 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.
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For icing,
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in a small bowl, combine the confectioners' sugar, milk and lemon juice; drizzle over cakes.