2 cups fresh or frozen blueberries (don't defrost if frozen) glaze:
1 cup confectioners' sugar
2 to 3 tablespoons 2% milk
Preheat oven to 350°. In a large bowl, cream butter and sugar until light and fluffy, 5-7 minutes. Add eggs, 1 at a time, beating well after each addition. Beat in vanilla. Combine the flour, baking powder, baking soda and salt; add to creamed mixture alternately with sour cream, beating well after each addition.
Spoon a third of the batter into a greased and floured 10-in. fluted tube pan. Combine brown sugar, flour and cinnamon; sprinkle half over batter. Top with half of the berries. Repeat layers. Top with remaining batter.
Bake 55-65 minutes or until a toothpick inserted in the center comes out clean. Cool 10 minutes before removing from pan to a wire rack to cool completely. Combine glaze ingredients; drizzle over coffee cake.