King Arthur's Favorite Fudge Cake

🥘 Ingredients

• butter (unsalted, 227g, cold, unsalted, 113g)
  24 tablespoons
• buttermilk or yogurt (113g, at room temperature, 85g)
  1/2 cup, 6 tablespoons
• cake**
• cocoa (unsweetened, 42g, Dutch-process or natural, unsweetened, 21g, Dutch-process or natural)
  3/4 cup
• confectioners' sugar (454g)
  4 cups
• eggs (large, at room temperature)
  2
• flour (king arthur unbleached all-purpose, 240g)
  2 cups
• frosting**
• king arthur pure vanilla extract
  1 teaspoon
• salt (table, to taste*)
  1/2-3/4 teaspoon
• soda (baking)
  1 teaspoon
• sugar (granulated, 397g)
  2 cups
• water (227g, hot)
  1 cup

🍳 Cookware

• pan
• bowl
• saucepan

1. 1

   Gather king arthur pure vanilla extract , frosting** , cake** .

   king arthur pure vanilla extract: 1 teaspoon, frosting**, cake**
2. 2

   Preheat the oven to 350°F. Grease and flour a 9" x 13" pan .

   flour: 2 cups (king arthur unbleached all-purpose, 240g)
3. 3

   To make the cake: Melt the butter ; stir in the cocoa and hot water . In a separate bowl , combine the flour, sugar , soda , and salt .

   butter: 16 tablespoons (unsalted, 227g, cold), cocoa: 1/2 cup (unsweetened, 42g, Dutch-process or natural), water: 1 cup (227g, hot), sugar: 2 cups (granulated, 397g), soda: 1 teaspoon (baking), salt: 1/2-3/4 teaspoon (table, to taste*)
4. 4

   Pour the cocoa mixture over the dry ingredients, stirring to blend. Beat in the buttermilk or yogurt , eggs , and vanilla. Pour the batter into the prepared pan.

   cocoa: 1/4 cup (unsweetened, 21g, Dutch-process or natural), buttermilk or yogurt: 1/2 cup (113g, at room temperature), eggs: 2 (large, at room temperature)
5. 5

   Bake the cake for ⏱️ 30 minutes , or until it tests done. You'll smell the chocolate aroma, and the cake will begin to pull away from the edge of the pan. Remove the cake from the oven and cool it on a rack.
6. 6

   To make the frosting: Melt the butter in a medium-sized saucepan . Stir in the cocoa and buttermilk or yogurt .

   butter: 8 tablespoons (unsalted, 113g), buttermilk or yogurt: 6 tablespoons (85g)
7. 7

   Bring the mixture to a boil, then remove it from the heat and mix in the confectioners' sugar , beating until smooth.

   confectioners' sugar: 4 cups (454g)
8. 8

   Pour the frosting over the cake while the frosting is still warm. Serve the cake right from the pan.
9. 📝

   Yield: One 9" x 13" cake

10. 📝

    **2026-03-16**

11. 📝

    Made this with the +50% cake recipe. The cake was really good, a bit denser than the Add a Pinch chocolate cake. I don't love that it uses just baking soda and no baking powder. Did not like the frosting very much. Need to go back to the King Arthur Yellow Cake frosting.

12. 📝

    **Thicker**

13. 📝

    This makes a typical sheet cake, which means it's fairly flat: about 1" to 1 1/4" tall. For a more substantial cake, one that's about 1 1/2" to 2" tall, increase all of the cake ingredients by 50%, and bake the cake for 40 to 45 minutes, until it tests done. The frosting measurements will remain the same.

14. 📝

    **Cupcakes**

15. 📝

    To bake as cupcakes: Line two muffin pans with cupcake papers and grease the papers. Preheat the oven to 350°F. Prepare the batter as directed above, then portion into the prepared pan, filling each well about 2/3 full.

16. 📝

    Bake the cupcakes for 21 to 23 minutes, until a paring knife inserted in the center of a cupcake comes out clean. Remove from the oven and cool in the pan for 5 minutes before tipping the cupcakes out of the pan to cool on a rack.

17. 📝

    To frost, make the frosting as directed and dip the cupcakes in the frosting while it’s still warm, letting the excess drip back into the pan. Sprinkle the tops with decorations before the frosting sets (this will happen quickly). If the frosting starts to set before you’ve dipped all the cupcakes, add a tablespoon of water and reheat gently, whisking until smooth.