Buttermilk Blueberry Crumb Cake

Makes one 8-inch cake, about 12 servings

  Nonstick cooking spray
For the crumb topping:
¾    cup plus 2 tablespoons unbleached all-purpose flour
6     tablespoons packed light brown sugar
6     tablespoons unsalted butter, room temperature,
       cut into tablespoons
1     teaspoon ground cinnamon
½    teaspoon pure vanilla extract
       Pinch kosher salt
For the buttermilk cake:
⅓ cups unbleached all-purpose flour
½ teaspoon baking soda
½ teaspoon cream of tartar
¼ teaspoon kosher salt 
⅓ cup unsalted butter, room temperature, cut into tablespoons
½ cup plus 2 tablespoons granulated sugar
1 large egg, room temperature
½ teaspoon pure vanilla extract 
⅓ cup buttermilk
2 cups blueberries, washed and dried well  

Nutritional information per serving (based on 12 servings):
Calories 270 (37% from fat) • carb. 39g • pro. 4g • fat 11g • sat. fat 8g chol. 46mg • sod. 196mg • calc. 15mg • fiber 1g

1. Lightly coat an 8-inch baking pan with nonstick cooking spray;
reserve.
2. Prepare the crumb topping by placing the flour, brown sugar, butter,
cinnamon, vanilla, and salt in a large mixing bowl. Mix together
using a hand mixer or by hand so that the mixture comes together
and forms large crumbs. Refrigerate until ready to use.
3. Prepare the cake. Stir the flour, baking soda, cream of tartar, and
salt together in a medium bowl and reserve.
4. Put the butter and granulated sugar into a large mixing bowl. Mix
together with a hand or stand mixer until light and fluffy.
5. Scrape the bowl well, and then add the egg and vanilla, mixing until
completely incorporated and smooth.
6. Add half the reserved dry mixture and then half of the buttermilk.
Mix until combined. Scrape the bottom and sides of the mixing
bowl. Add the remaining dry ingredients and buttermilk. Continue
mixing on low speed until smooth and blended.
7. Pour the batter into the prepared pan and smooth the top. Sprinkle
the blueberries evenly over the top, and then lightly press them into
the batter so that they are slightly submerged.
8. Breaking up any large clumps, crumble the topping over the blueberries to evenly coat.
9. Select Bake, and set the time to 45 minutes and the temperature to
325°F. Press Start/Stop. Once the unit is preheated, add the cake
to the basket. The cake is finished when the crumb topping is evenly browned and a cake tester comes out clean from the center of
the pan. Add additional time in 5-minute increments should the
cake need more baking time.
10. Transfer the cake to a wire rack. Cool completely before cutting and
serving.