Blueberry Buttermilk Coffeecake

Step 1
Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9×13 inch pan.

Step 2
Sift flour, baking powder, baking soda, and salt together in a bowl. Set aside.

Step 3
In a large bowl, cream together sugar and butter until light and fluffy. Beat in eggs one at a time, then stir in the vanilla. Beat in the flour mixture alternately with the buttermilk, mixing just until incorporated. Sir in blueberries. Pour batter into prepared pan.

Step 4
In a small bowl, combine flour and sugar. Cut in butter until mixture resembles coarse crumbs. Sprinkle over top of batter.

Step 5
Bake in the preheated oven for 45 to 60 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool.