5,2 / 10
ready in 3 h. 25 min.
Position oven rack in the center of oven. Preheat oven to 350º F / 180º C. Coat a standard size loaf pan with nonstick cooking spray or butter. Dust lightly with flour.
In the bowl of an electric mixer or with a hand mixer, beat the butter until smooth. Gradually add the sugar and beat until light and fluffy, about 4 minutes. Scrape down the sides of the bowl as necessary. Add eggs, one at a time, beating well after each addition. Beat in the vanilla extract.
In a separate bowl, sift the flour, baking powder, baking soda and salt together. Add the flour mixture and 1/2 cup of milk to the egg batter, in three additions starting and ending with flour; mix well.
Pour half the batter into a separate bowl. Add the cocoa powder and the remaining milk.
Pour the batter into the prepared loaf pan, alternating between the two batters. Marble the batter with the end of a wooden spoon by gently drawing swirls through the batter. Do not over mix.
Bake for 50 to 60 minutes, or until a wooden toothpick inserted in the center of the cake comes out clean. Allow to cool in the pan on a wire rack for 10 minutes before removing the cake from the pan to cool completely. Sprinkle generously with confectioners' sugar prior to slicing and serving.