Step 1

Preheat the oven to 350 degrees F.

Step 2

Grease and flour a 9-inch, 10-cup Bundt pan.

Step 3

In a large mixing bowl, beat the butter and the sugar until light and fluffy, about 2-3 minutes.

Step 4

Add the eggs to the butter mixture, one at a time, and beat well after each addition. Scrape down the bottom and the sides of the bowl.

Step 5

Add the sour cream and the vanilla to the butter mixture and mix until combined.

Step 6

Add the flour, the baking powder, and the salt to the butter mixture and mix just until blended.

Step 7

Gently fold the blueberries into the batter.

Step 8

Spoon 1/2 of the batter into the prepared Bundt pan.

Step 9

In a medium bowl, add the brown sugar, the cinnamon, and the walnuts and stir to combine.

Step 10

Sprinkle the brown sugar mixture over the batter in the pan.

Step 11

Spoon the remaining batter over the top of the brown sugar mixture layer and smooth it out.

Step 12

Bake the cake until a knife inserted into the cake comes out clean with just a few crumbs, about 55 minutes-1 hour 20 minutes.

Step 13

Allow the cake to cool in the pan for 10 minutes.

Step 14

Invert the pan onto a cake plate and allow the cake to cool completely.

Step 15

Dust the cake with the powdered sugar just before serving.

Step 16

Serve.