Preheat your oven to 350 degrees and grease and flour a 9 inch pan in a large bowl cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time. Stir in the sour cream and vanilla.

Combine the flour, baking powder and salt and stir it into the butter mixture until well blended.

Fold in the blueberries spoon half of the batter into prepared bundt pan.

In a small bowl combine the brown sugar and cinnamon. Sprinkle half of the brown sugar mixture over the batter in the pan and top with the second half of the batter. Sprinkle the rest of the brown sugar mixture over the top of everything.

Bake the cake for 55 to 60 minutes in preheated oven. Cool cake in the pan on a wire rack about 10 minutes before turning out onto a cake plate