Serves 10
Ingredients:
Semisweet Chocolate - 5 ounces (140 grams)
All Purpose Flour - 2 1/4 cups
Baking Powder - 2 1/2 tsps
Baking Soda - 1/4 tsp
Salt - 1/2 tsp
Unsalted Butter - 3/4 cup at room temperature
Granulated White Sugar - 1 1/4 cups
Eggs - 3 large at room temperature
Vanilla Extract - 1 1/2 tsps
Sour Cream or Plain Yogurt - 1/3 cup at room temperature
Milk - 1/2 cup at room temperature
Method:
Preheat the oven to 350 degrees F (180 degrees C) and place the rack in center of the oven. Butter, or spray with a non stick spray, a 10 inch (25 cm) bundt or tube pan.
In a heatproof bowl, placed over a saucepan of simmering water, melt the chocolate. Remove from heat and set aside to cool to room temperature.
Meanwhile, in a separate bowl, sift or whisk together the flour, baking powder, baking soda, and salt.
In the bowl of your electric mixer (or with a hand mixer), beat the butter until smooth. Gradually add the sugar and continue to beat until the mixture is light and fluffy (about 3-5 minutes). Scrape down the sides of the bowl as needed. Add eggs, one at a time, beating well after each addition. Beat in the vanilla extract and sour cream.
With the mixer on low speed, alternately add the flour mixture and the milk to the batter, in three additions, beginning and ending with the flour. Remove a little more than half of the batter and place into a separate bowl. To the remaining batter stir, or beat, in the melted chocolate. Place the batters into the prepared bundt pan by alternating spoonfuls of vanilla batter with the chocolate batter. Then, with the end of a wooden skewer or knife, gently draw swirls through the batter to marbleize it. Don't over mix.
Bake for about 35 - 40 minutes, or until a toothpick inserted in the center just comes out clean. Remove from oven and place on a wire rack to cool for about 20 minutes before removing the cake from the pan to cool completely. Can dust the top of the cake with cocoa powder or powdered sugar. Serve warm or at room temperature. This cake is best the day it's made, but it will keep for a couple of days at room temperature or it can be frozen.