Ingredients:

  • 2 ½ cups (300g) all-purpose flour, plus more for dusting the pan
  • 1 teaspoon baking powder
  • ½ teaspoon baking soda
  • ½ teaspoon salt
  • 1 cup (226g) unsalted butter, softened, plus more for greasing the pan
  • 1 ¾ cups (350g) granulated sugar
  • 2 large eggs
  • 1 teaspoon vanilla extract
  • 1 cup (240ml) buttermilk
  • ¼ cup (25g) unsweetened cocoa powder
  • 2 tablespoons (30ml) hot water
  • 1 tablespoon (15ml) milk or cream
  • 1 cup (120g) confectioners' sugar (optional glaze)
  • 2-3 tablespoons milk, cream, or lemon juice (optional glaze)

Instructions:

  1. Grease and flour your 9x5 inch loaf pan. Preheat oven to 350°F (175°C).
  2. Whisk together flour, baking powder, baking soda, and salt in a medium bowl.
  3. Cream together softened butter and granulated sugar until light and fluffy.
  4. Beat in eggs one at a time, then stir in vanilla extract.
  5. Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined; do not overmix.
  6. Divide the batter evenly into two separate bowls.
  7. In one bowl, whisk together cocoa powder and hot water to form a paste. Add this paste and the milk/cream to one bowl of the batter and mix until evenly combined.
  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, being careful not to overmix.
  10. Bake for 45-55 minutes, or until a toothpick inserted into the center comes out clean.
  11. Let cool in the pan for 10 minutes before transferring to a wire rack to cool completely.
  12. Whisk together confectioners' sugar and milk/cream/lemon juice until smooth (for optional glaze). Drizzle over cooled cake.