• Preheat oven to 350 degrees; grease a 9 x 13″ pan.
• Cream together the butter, sugar and brown sugar.
• Whip in the sour cream, eggs and vanilla.
• Fold in the flour, baking powder and salt.
• Spread into prepared pan.
• Sprinkle the blueberries on top.
• Sprinkle some sugar on top of the blueberries.
• Bake for 25-30 minutes; until a toothpick stuck in the center comes out clean.

Glaze:

• Make the glaze by mixing the butter, powdered sugar and vanilla together. Add enough milk to get a creamy consistency.
• Spread it on the cake while it’s still warm.
• Slice, serve and enjoy!