when colors are swirled together, they catch my eye. the intricate pattern created by the marbleization of two or more colors has always fascinated me. it can be paint or it can be cake, doesn’t matter. one of my favorite mediums for marbleizing is biscotti dough but cheesecake is a close second. then there are bundt cakes; my new favorite “canvas” for mixing swirls of color. almost as much fun as choosing the colors is choosing the flavors to combine. if chosen correctly, it is a perfect yin and yang of both color and flavor.
working the marbleizing magic with cake batter is a little tricky. depending on your leavening agent, the colors can shift. baking soda can give blueberries, blackberries and raspberries a greenish tint that is not very pleasing but it will turn chocolate a much darker brown or even black. baking powder on the other hand will keep the berries looking like their natural shades of purple and red but will cause the chocolate to turn a muddy red. to further complicate things, mixing two completely different cake batters can be difficult since they may not bake the same. finding the balance is part of the challenge. luckily, dutched cocoa powder is not hard to find and that makes it a little easier to prevent the color shift. and for those of you who cannot find the dutch process cocoa, try adding a small amount of baking soda to simulate the higher alkaline content; i added an 1/8 teaspoon to the 1/3 cup of cocoa and had good results.
mocha swirl bundt cake
1 10 cup bundt serving about 12
1/3 cup dutch processed cocoa powder (or 1/3 cup natural cocoa and 1/8 teaspoon baking soda)
2 tablespoons instant espresso powder
1/3 cup boiling water
10 tablespoons unsalted butter, softened
1 1/2 cup sugar
2 teaspoons vanilla
1/2 teaspoon salt
3 cups cake flour
5 teaspoons baking powder
1 1/3 cup buttermilk
preheat the oven to 350. grease and flour a bundt pan and set it aside. in a small heat proof bowl, whisk the cocoa and espresso powder to combine. add the boiling water and stir to make a smooth paste, set this aside while you mix the batter.
to mix the batter, cream the butter with the sugar, vanilla and salt until it is light and fluffy, about 3-5 minutes. add the eggs one at a time and mix until combined, scrape the bowl as you go. sift the cake flour and the baking powder over the top of the batter. fold this a couple times and then sprinkle the buttermilk over the top of the batter. fold the batter together until it is just combined. remove 2 cups of the batter and stir it into the chocolate paste. place dollops of batter into the prepared pan, alternating between dark and light. using a skewer or thin knife, carefully swirl the batters by dragging it through and stirring it occasionally. be careful not to go overboard or the pattern will not be visible after baking. bake until a pick inserted into the cake comes out clean, about 45 minutes. allow the cake to cool in the pan for about 20 minutes. turn the cake out onto a serving plate and allow it to finish cooling.