Chocolate Sour Cream Pound Cake

Position a rack in the center of the oven and preheat the oven to 325°F. Grease the inside of a 10-inch Bundt pan with baking spray that contains flour.
In a large bowl, whisk the flours, cocoa powder, baking powder, and salt.
In a bowl of an electric mixer, using the paddle attachment, beat the butter (make sure butter is softened in microwave first) at medium speed. Gradually beat in the sugar, until light and creamy. At medium speed, beat in the eggs one at a time, mixing well after each addition.
In a small bowl, stir the vanilla extract into the sour cream. At the low speed, add the dry ingredients to the butter mixture in 3 additions, alternating with the sour cream mixture in 2 additions and mixing just until blended.
Bake the cake for 65 to 75 minutes, until a flat knife inserted into the center comes out clean. Cool the cake in the pan on a wire rack for 15 minutes. Then invert the cake onto the rack and let it cool completely.