Ingredients:

  • 1.75 cups (210g) All-purpose flour
  • 1 cup (200g) Granulated sugar
  • 1 tsp Baking powder
  • 0.5 tsp Baking soda
  • 0.5 tsp Sea salt
  • 0.75 cup (170g) Unsalted butter, softened (65°F)
  • 2 Large eggs, room temperature
  • 0.5 cup (120g) Full-fat Greek yogurt
  • 2 tsp Pure vanilla extract
  • 0.33 cup (30g) Dutch-processed cocoa powder
  • 0.25 cup (50g) Granulated sugar
  • 3 tbsp Boiling water
  • 1 tbsp Melted butter

Instructions:

  1. Preheat oven to 350°F (180°C). Grease a 9x5 inch loaf pan and line with parchment paper.
  2. Whisk dry ingredients. Combine 1.75 cups (210g) flour, 1 tsp baking powder, 0.5 tsp baking soda, and 0.5 tsp salt.
  3. Cream butter and sugar. Beat 0.75 cup (170g) softened butter and 1 cup (200g) sugar until pale, fluffy, and increased in volume.
  4. Incorporate eggs and vanilla. Add 2 eggs one at a time, beating well after each. Stir in 2 tsp vanilla.
  5. Alternate wet and dry. Add flour mixture in three parts, alternating with 0.5 cup (120g) yogurt, until just combined and no streaks remain.
  6. Prepare the chocolate paste. In a small bowl, whisk 0.33 cup (30g) cocoa, 0.25 cup (50g) sugar, 3 tbsp boiling water, and 1 tbsp melted butter until glossy and smooth.
  7. Create the chocolate batter. Remove 1 cup of the vanilla batter and fold it into the chocolate paste.
  8. Layer the batters. Drop large spoonfuls of vanilla and chocolate batter into the pan in an alternating checkerboard pattern.
  9. Execute the swirl. Use a butter knife to swirl the batters together in a figure-8 motion until loosely marbled but not blended.
  10. Bake 55 minutes. Cook until a skewer comes out clean and the top is golden.