Chocolate Streusel Coffee Cake

1 1/2 cup flour
3/4 cup sugar
1 tsp cinnamon
3/4 tsp baking powder
1/4 tsp baking soda
1/2 tsp salt
1/2 cup butter, cut into small pieces
2/3 cup buttermilk
1 egg
1 tsp pure vanilla extract

Chocolate Streusel Topping
1/4 cup flour
1/4 cup brown sugar
1 Tbsp unsweetened cocoa powder
3 Tbsp butter, cut into small pieces
1/4 cup semi sweet chocolate chips

Set oven to 350 degrees. Grease an 8 inch square pan and set aside.

In a large bowl, combine flour, sugar, cinnamon, baking powder, baking soda and salt. Whisk to combine. Add butter and cut into coarse crumbs with a pastry blender. Add buttermilk, egg and vanilla. Beat with a hand mixer on medium speed for 1 minute, or until well blended. Spread in pan.

In a small bowl, combine flour, brown sugar, cocoa powder and butter. Using a pastry blender, cut butter into coarse crumbs. Sprinkle over the top of the batter. Sprinkle chocolate chips on top.

Bake for 35-40 minutes, or until a toothpick inserted comes out clean. Cool for 15 minutes. Serve warm.