Ingredients:

  • 225g (1 cup, 2 sticks) unsalted butter, softened, US
  • 225g (1 cup) granulated sugar, US
  • 2 large eggs, US
  • 1 teaspoon vanilla extract
  • 280g (2 ¼ cups) all-purpose flour, US
  • 2 ½ teaspoons baking powder
  • ¼ teaspoon salt
  • 240ml (1 cup) whole milk
  • 3 tablespoons unsweetened cocoa powder
  • 2 tablespoons hot water
  • 1 tablespoon granulated sugar, US

Instructions:

  1. Preheat oven to 350°F (175°C). Grease and flour a 9x5 inch loaf pan.
  2. In a large bowl, cream together softened butter and granulated sugar until light and fluffy (about 3-5 minutes).
  3. Beat in eggs one at a time, then stir in vanilla extract.
  4. In a separate bowl, whisk together flour, baking powder, and salt.
  5. Gradually add the dry ingredients to the wet ingredients, alternating with the milk, beginning and ending with the dry ingredients. Mix until just combined; do not overmix.
  6. Divide the batter in half into two separate bowls.
  7. In one of the bowls, combine cocoa powder, hot water, and sugar. Mix until smooth.
  8. Spoon alternating dollops of vanilla and chocolate batter into the prepared loaf pan.
  9. Use a toothpick or skewer to gently swirl the batters together, creating a marbled effect. Be careful not to over-swirl.
  10. Bake for 45-55 minutes, or until a toothpick inserted into the center comes out clean.
  11. Let the cake cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.