Marble Cake with White-Chocolate Glaze

Preparation

1. Step 1

   Preheat the oven to 350°F. Generously butter a 9-by-5-inch loaf pan; set aside. Whisk together the cake flour, baking powder, and salt; set aside.

   Step 2

   In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and sugar until light and fluffy, about 5 minutes. Add the eggs one at a time, beating until combined after each addition and scraping down the sides of the bowl as needed. Mix in the vanilla. Add the flour mixture in two batches, alternating with the buttermilk and beginning and ending with the flour. Set aside one-third of the batter.

   Step 3

   In a bowl, mix the cocoa and the boiling water with a rubber spatula until smooth. Add the cocoa mixture to the reserved cake batter; stir until well combined.

   Step 4

   Spoon the batters into the prepared pan in two layers, alternating spoonfuls of vanilla and chocolate to simulate a checkerboard. To create marbling, run a table knife (or wooden skewer) through the batters in a swirling motion.

   Step 5

   Bake, rotating the pan halfway through, until a cake tester comes out clean, 40 to 50 minutes. Transfer pan to a rack to cool 10 minutes. Turn out cake from the pan and cool completely on the rack. Pour glaze over cake, letting it drip down the sides. Cake can be kept in an airtight container at room temperature for up to 3 days.

2. White-Chocolate Glaze

   Step 6

   In a small bowl, whisk together the confectioners’ sugar and milk.The mixture should have the consistency of thin sour cream. Add the melted chocolate and whisk until glaze is smooth. If it is too thin, add more sugar, 1 tablespoon at a time; if too thick, add more milk, 1 teaspoon at a time. Use immediately.

3. Marbleizing how-to

   Step 7

   Spoonfuls of vanilla and chocolate batters are alternated, in two layers, in a checkerboard pattern.

4. Step 8

   A table knife is run through the batters to create swirls.