Chocolate Espresso Marble Cake

Preheat an oven to 350°F (180°C). Grease and flour a 10- to 12-cup (2.5- to 3-l) Bundt pan or a 1 1/2-lb. (750-g) loaf pan. Place the pan on a rimmed baking sheet.

Put the espresso powder in a small bowl, add the hot water and stir to combine; set aside.

In the bowl of an electric mixer fitted with the flat beater, beat together the butter and sugar on medium speed until light and fluffy, about 5 minutes. Add eggs and egg yolks one at a time and beat until fully incorporated, about 1 minute. Stop the mixer and scrape down the sides of the bowl. Add the sour cream, vanilla and salt and beat on medium speed until combined, about 1 minute.

Divide the batter in half and place in separate bowls. You can eyeball this or use a kitchen scale to be more precise; each portion should weigh about 1 lb. (500 g). To the batter in one bowl, sift in 1 cup (4 oz./125 g) of the flour. Using a rubber spatula, fold in the flour until no dry streaks remain. This is the vanilla batter.

To the batter in the other bowl, sift in the remaining 1/2 cup (2 oz./60 g) flour and the cocoa powder. Using a rubber spatula, fold in the flour and cocoa until no dry streaks remain, then stir in the espresso mixture. This is the chocolate batter.

Pour about one-third of the vanilla batter into the prepared pan, then top with about one-third of the chocolate batter. Continue adding the vanilla and chocolate batters in alternating layers to make a total of six layers. In one continuous “S” formation, drag a table knife through the batter to create a swirl, then switch directions and swirl again. Repeat the swirling in both directions two more times until the batter is beautifully swirled.

Bake until a toothpick inserted into the center of the cake comes out clean, about 55 minutes if using a Bundt pan and 85 minutes if using a loaf pan.

Transfer the pan to a wire rack and let cool for 15 minutes, then invert the pan onto the rack and lift off the pan. Let the cake cool for 25 minutes and serve warm, or let cool completely and serve at room temperature. Serves 10 to 12.

Williams Sonoma Test Kitchen