Ingredients:

  • 2 cups (250g) all-purpose flour
  • 2 cups (400g) granulated sugar
  • 1 cup (226g) unsalted butter
  • 1 cup (237ml) water
  • 1/4 cup (25g) unsweetened cocoa powder (for cake)
  • 1/2 cup (120ml) buttermilk, room temperature
  • 2 large eggs, room temperature
  • 1 tsp baking soda
  • 1 tsp vanilla extract (for cake)
  • 1/2 tsp salt
  • 1/2 cup (113g) unsalted butter (for frosting)
  • 1/4 cup (25g) unsweetened cocoa powder (for frosting)
  • 6 tbsp (90ml) whole milk
  • 3 cups (375g) confectioners’ sugar, sifted
  • 1 tsp vanilla extract (for frosting)
  • 1 cup (125g) chopped pecans, toasted

Instructions:

  1. Preheat your oven to 350°F (180°C) and grease your 18x13 inch sheet pan thoroughly. Note: This prevents the delicate sponge from sticking to the corners.
  2. Whisk the 2 cups flour, 2 cups sugar, and 1/2 tsp salt in a large bowl. Make sure there are no large sugar clumps.
  3. In a saucepan, combine 1 cup butter, 1 cup water, and 1/4 cup cocoa. Bring to a full rolling boil at 212°F.
  4. Pour the boiling mixture over the dry ingredients. Whisk until just combined. Note: The heat will start to dissolve the sugar immediately.
  5. Stir in the 1/2 cup buttermilk, 2 eggs, 1 tsp baking soda, and 1 tsp vanilla. Whisk until the batter is velvety and smooth.
  6. Pour into the prepared pan and bake for exactly 20 minutes until the center springs back.
  7. While the cake bakes, start the frosting about 5 minutes before the timer goes off.
  8. Boil the 1/2 cup butter, 1/4 cup cocoa, and 6 tbsp milk in a clean saucepan. Remove from heat as soon as it bubbles.
  9. Whisk in the 3 cups sifted confectioners' sugar and 1 tsp vanilla. The mixture should be glossy and pourable.
  10. Fold in the toasted pecans and pour the hot frosting over the hot cake immediately. Spread quickly before it begins to set.