Deep Chocolate Sour Cream Pound Cake

This was the first recipe I've tried from The Cake Book. I thought I had a close to perfect chocolate pound cake already, but this one blew it out of the water. It is intense, deep, and rich, and though she suggests glazing it, I think that would be overkill. It is deadly good for snacking on, and keeps fantastically.

1 1/2 c all-purpose flour
1/2 c cake flour
1 c Dutch-processed cocoa powder
2 1/4 tsp baking powder
1/2 tsp salt
1 1/2 c unsalted butter, softened
2 1/2 c granulated sugar
4 large eggs
2 tsp vanilla extract
1 c sour cream

1. Position a rack in the center of the oven. Preheat to 325F. Grease and flour a 10-inch Bundt pan.
2. Sift together the flours, cocoa powder, baking powder, and salt in a medium bowl, and set aside.
3. Beat the butter until very creamy, about two minutes. Gradually beat in the sugar and beat until well blended and light, about four minutes. Beat in the eggs one at a time, mixing well after each addition and scraping the bowl as needed. 
4. In a small bowl, stir the vanilla extract into the sour cream (I don't know why she has this step; I put the vanilla in after the eggs, which almost every other recipe I have does). If your mixer has a splatter shield, attach it now (would that mine did!). At low speed, add the dry ingredients to the butter in three additions, alternating with the sour cream in two additions, mixing just until blended. Scrape the batter into the prepared pan and smooth the top.
5. Bake 65-75 minutes or until a cake tester comes out clean. Cool in the pan on a rack 15 minutes. 
6. Invert the cake onto a rack and cool completely.