Blueberry Coffee Cake - WTF and WOW Recipe Wednesday

Blueberry Coffee Cake (www.joyofbaking.com)

Ingredients
Streusel Topping:
1/3 cup (45 grams) all purpose flour
1/3 cup (65 grams) granulated white sugar
1/2 teaspoon ground cinnamon
1/4 cup (56 grams) cold unsalted butter, cut into pieces
Cake Batter:
1 cup (130 grams) all purpose flour
1 teaspoon baking powder
1/8 teaspoon salt
1/4 cup (56 grams) (4 tablespoons) unsalted butter, room temperature
1/2 cup (100 grams) granulated white sugar
1 large egg
1/2 teaspoon pure vanilla extract
1/3 cup (80 ml) milk
2 cups fresh blueberries

Preparation
Blueberry Cake Recipe: Preheat oven to 350 degrees F (177 degrees C).  Butter, or spray with a
nonstick vegetable spray, an 8 x 8 inch (20 x 20 cm) square pan or an 8 inch (20 cm) round cake
pan. 
For streusel topping:  In a large bowl, mix together the flour, sugar, and ground cinnamon.  Cut in the
butter with a pastry blender or fork until it resembles coarse crumbs.  Set aside while you make the
cake batter.
In a separate bowl whisk together the flour, baking powder, and salt.  Set aside.
In the bowl of your electric mixer, or with a hand mixer, beat the butter until smooth.  Add the sugar
and beat until light and fluffy.  Add the egg and vanilla and beat until incorporated.  Add the flour
mixture, alternately with the milk, and beat only until combined.  Spread the batter onto the bottom
of the prepared pan, smoothing the top with an offset spatula. 
Evenly arrange the blueberries on top of the cake batter and then sprinkle with the streusel topping.
Bake for about 40 - 50 minutes or until a toothpick inserted in the center of the cake comes out
clean.  Remove from oven and place on a wire rack to cool slightly. 
Serve warm or at room temperature.