Blueberry Coffee Cake

1. Preheat oven to 350°F. Coat an 8-inch-square pan with cooking spray.
2. Prepare streusel by mixing together the dry streusel ingredients and then cutting in butter by hand.
3. For the cake, sift flour, baking powder, cinnamon, baking soda and salt together in a large bowl. Set aside.
4. Cream sugar and eggs until light and frothy, about 3 minutes. The mixing attachement should leave a trail when lifted. Set aside.
5. Combine buttermilk, oil and vanilla. Alternate adding the wet ingredients and dry ingredients into the egg mixture, beginning and ending with the flour mixture. Fold in blueberries.
6. Spread half the batter into the prepared pan. Sprinkle half the streusel on top. Spoon in the remaining batter and top with the remaining streusel.
7. Bake the coffee cake about 35-40 minutes until a knife inserted in the center comes out clean.