Preheat oven to 325º F. Spray 8-inch square pan with vegetable pan spray.
In large bowl, cream butter and sugar in large bowl with electric mixer until light and fluffy. Add eggs and vanilla; beat well. Combine flour, baking powder, baking soda and salt. Add alternately with sour cream to butter mixture. Mix until smooth. In a small bowl, combine nuts, brown sugar and cinnamon.
Spread half the batter into prepared pan. Mix blueberries with 3/4 cup nut mixture; sprinkle over batter. Top with remaining batter. Sprinkle with remaining nut mixture. Bake 35-40 minutes or until cake tester inserted in middle comes out clean.