Marble Pound Cake
Adapted from Bakefromscratch.com
- 2 cups unsalted butter, room temperature and divided
- 3 cups granulated sugar, divided
- 3 tsp vanilla extract,divided
- 4 large egg whites,room temperature
- 4 ounces (115 grams) white chocolate, melted
- 2 ¼ cups cake flour, divided
- 2 tsp kosher salt, divided
- 2 large eggs, room temperature
- 4 large egg yolks, room temperature
- 3/4 cup (Dutch process) cocoa powder, sifted
- ½ cup whole buttermilk, room temperature
Butter and flour a 10-inch Bundt pan or angel food cake pan with removable bottom.
In the bowl of a stand mixer with the paddle attachment, beat 1 cup butter, 11⁄2 cups sugar, and 1 ½ teaspoons vanilla at medium speed until fluffy and pale, a minimum of 6 minutes. Add egg whites one at a time, beating well after each addition, about 15 seconds, and scraping down sides with a rubber spatula. With mixer on medium-high speed, add melted white chocolate, beating until smooth, about 1 minute. Add 1 ½ cups flour and 1 teaspoon salt, and stir with a rubber spatula just until combined. Scrape white batter into a bowl, and set aside.
Return bowl to stand mixer. With the paddle attachment, beat remaining 1 cup butter, remaining 1 ½ cups sugar, and remaining 1 ½ teaspoons vanilla at medium speed until fluffy and pale, at least 6 minutes. Add eggs, one at a time, beating well after each addition, about 15 seconds. Add egg yolks, two at a time, beating well after each addition, about 15 seconds. Scrape bottom and sides of bowl with a rubber spatula. With mixer on medium-high speed, beat until smooth, about 1 minute. Add cocoa, remaining ¾ cup flour, and remaining 1 teaspoon salt. With mixer on low speed, add buttermilk, beating just until batter comes together. Scrape bottom and sides of bowl with a rubber spatula, and stir just until combined.
Using a large (2- to 3-ounce) spring-loaded ice cream scoop, alternately scoop white and black batters into prepared pan. Tap pan lightly on counter to settle batter.
Place pan in a cold oven, and bake at 300°F (150°C) until lightly browned on top and a wooden pick inserted near center comes out clean, 1 ½ to 2 hours. (This bake time depends on how long it takes your oven to preheat. Start checking after 1 ½ hours, and continue baking in 10-minute intervals until cake is done.) Let cool in pan on a wire rack for 10 minutes. Invert cake onto wire rack, and unmold from pan. Let cool completely.