Blueberry Sour Cream Coffee Cake

Instructions

1. 1
   Prepare the streusel by mixing brown sugar, cinnamon, 1/2 cup flour, and cold butter until crumbly. Chill.
2. 2
   In a large bowl, cream together softened butter and granulated sugar until fluffy.
3. 3
   Beat in eggs one at a time, then add vanilla.
4. 4
   In a separate bowl, whisk together 2 cups flour, baking powder, baking soda, and salt.
5. 5
   Add dry ingredients to the butter mixture in three additions, alternating with sour cream. Mix until just combined.
6. 6
   Fold blueberries gently into the batter.
7. 7
   Spread half the batter in a greased 9-inch square pan. Top with half the streusel, then the rest of the batter, and finish with the remaining streusel.
8. 8
   Bake at 350°F (175°C) for 38-42 minutes or until a toothpick comes out clean.
9. 9
   Cool at least 20 minutes before slicing and serving.