1Preheat oven to 350 degrees. Combine butter and 1 cup brown sugar. Whisk until light and fluffy. Add eggs, sour cream and vanilla; mix well. Gradually stir in flour, baking powder, baking soda and salt; mix well. Fold in blueberries.
2Combine filling ingredients; mix well. Spoon half of batter into well sprayed springform pan fitted with fluted bottom. Spread filling evenly over batter. Top with remaining cake batter. Bake at 350 degrees for 45 to 50 minutes. Let cool in pan for 10 minutes. Carefully run a knife around outer edges of cake.