Cake Mix Sour Cream Coffee Cake

Steps

1. 1

   Preheat oven to 350°F. Grease an 8" or 9" square pan and line with a parchment sling .

2. 2

   To make the crumb topping : In a medium bowl, add the 1 cup (156g) of cake mix, cinnamon, and chopped nuts. Then add the melted butter, stirring to form soft crumbs. Set aside.

3. 3

   To make the cake : Place the remaining cake mix into the bowl of a stand mixer fitted with the flat beater attachment. Mix in the baking soda, then add the softened butter and beat on low speed to form small, uniform crumbs, 1 to 2 minutes. Beat in the eggs one at a time, scraping down the sides and bottom of the bowl as needed; you will have a smooth, thick batter. Scrape down the bowl, add the sour cream, and beat until no white streaks remain, about 30 seconds.

4. 4

   Spread the batter into the greased pan then sprinkle the blueberries over the batter.

5. 5

   Distribute the crumb topping evenly over the batter, squeezing to form some larger crumbs.

6. 6

   Bake for 35 to 40 minutes in an 8" square or 32 to 38 minutes in a 9" square, or until a toothpick inserted into the center comes out clean or with a few moist crumbs sticking to it. If using blueberries, increase the baking time by an additional 10 to 12 minutes.

7. 7

   Remove the coffee cake from the oven and let it cool for 15 minutes on a wire rack before serving from the pan or using the parchment sling to transfer it to a cutting board or plate. Dust with confectioners’ sugar or non-melting sugar , if desired.

8. 8

   Storage information: Wrap the completely cooled coffee cake airtight and store at room temperature for several days: freeze for longer storage.

9. 9

   If you’re using a 20-ounce box of Golden Yellow Cake, the amount of mix in the cake batter will be the entire remainder of the box after you’ve measured out the 1 cup for the topping. If you’re using the 24-ounce box, you’ll want to measure out the 2 2/3 cups (416g), as there will be some mix left over.