MAKES 1 3-tier 20cm (8") cake (I made a 2-tier, 18cm cake and 12 cupcakes. If you decide to do this, too, note that the cupcakes will only take approx. 15mins to bake.)
PREPARATION 25-30minutes
COOKS 30-35minutes
(you'll need an electric mixer for this recipe)

For the sponge

  • 2 cups all-purpose flour
  • 2 1/2 cups sugar
  • 3/4 cup unsweetened cocoa powder
  • 2 teaspoons baking powder
  • 1 teaspoon salt
  • 1 cup neutral vegetable oil (I used sunflower oil)
  • 1 cup sour cream
  • 1 1/2 cups water
  • 2 tablespoons distilled white vinegar
  • 1 teaspoon vanilla extract
  • 2 eggs

 For the icing

  • 285g (10 ounces) cream cheese, at room temperature
  • 115g (4 ounces) unsalted butter, at room temperature
  • 5 cups icing sugar, sifted
  • 2/3 cup smooth peanut butter
  • 150g grated dark chocolate



  1. Preheat the oven to 175˚C.  Butter the bottoms and sides of three 8" (20cm) round cake tins. Line the bottom of each pan with a round of baking or waxed paper and butter the paper.
    Note: If you don't have 3 cake tins (or 2 in my case), or an oven big enough to accommodate all tins, you can bake one layer at a time. It takes a little extra time but the hassle is 0.
  2. Sift the flour, sugar, cocoa powder, baking soda, and salt into a large bowl. Whisk to combine them well. Add the oil and sour cream and whisk to blend. Gradually beat in the water. Blend in the vinegar and vanilla. Whisk in the eggs and beat until well blended. Scrape down the sides of the bowl and be sure the batter is well mixed. Divide among the prepared cake tins.
  3. Bake for 30 to 35 minutes, or until a wooden toothpick inserted in the center comes out almost clean. Let cool in the pans for about 20 minutes. Invert onto wire racks and let cool completely. Note: this cake is super soft and springy and I found it easier to keep the baking paper on until the last minute. If you have enough space, ideally place them into the fridge until you're ready to ice. 
  4. While your sponge is cooling, beat the cream cheese and butter in a large bowl with an electric mixer, until light and fluffy. Gradually add the icing sugar, 1 cup at a time, mixing thoroughly after each addition and scraping down the sides of the bowl often. Continue to beat on medium speed until light and fluffy, 3 to 4 minutes. 
  5. Add the peanut butter and beat until thoroughly blended.
  6. To frost the cake, place one layer, flat side up, on a cake stand or large serving plate. Spread 2/3 cup of the peanut butter frosting evenly over the top. Repeat with the next layer. Place the last layer on top and frost the top and sides of the cake with the remaining frosting. Note: Make sure you crumb your cake first to avoid any bits of sponge showing in your frosting. If you've never iced a cake before this video is great! 
  7. Leave the iced cake to cool in the fridge for a couple of hours or overnight. Cover with the grated chocolate and serve.