• Preheat Oven to 325 degrees Fahrenheit
• Grease a Bundt Pan with some spray stuff or butter
• In a stand mixer, cream butter and sugar until light and fluffy.... 5 or minutes.
• Add Vanilla... beat in.
• Add Eggs, one at a time...beating and scraping between each egg.
• Scrape often, and make sure each egg is completely incorporated before adding another.
• Combine flour, baking powder and baking soda in a larger measuring cup.
• Alternate adding flour mixture and sour cream into the butter mixture, beat at low speed all the while, until the ingredients are just combined.
• Now.....
• Take half of the batter, and spread it into the bottom of the prepared bundt pan. Set aside.
• To the rest of the batter, add the cocoa powder and the milk. Beat until completely combined.
• Spread the chocolate batter over the vanilla batter.
• Using a knife, swirl the two flavors together by scooping in and up and over..... sort of like folding. Don't go bananas and make it a total mix, just swirl them a bit.
• Put in the oven and bake for 1 hour and 5 minutes. (1 hour if you are using a guglehopf pan instead of a bundt)
• Check.... a toothpick inserted should come out clean. If it doesn't .... add some time.
• Let cool in pan on rack for 15 minutes.... Then turn out of pan.
• Let cool completely.
• Sprinkle with Powdered Sugar or Make an Icing

Icing:

• Stir or whisk all icing ingredients until combined. If it's thick...add more milk... if it's thin... add more sugar.