Go Back

Chocolate Spider Web Sheet Cake

A simple and bewitchingly moist chocolate sheet cake to sink your teeth into, topped with a fudgy chocolate ganache and spider web design.
Course Dessert
Keyword Cake, Chocolate, Halloween
Prep Time 30 minutes
Cook Time 45 minutes


  • 9 x 13" pan
  • Cocktail stick/Toothpick or skewer
  • Piping bag


Chocolate Cake

  • 225 g / 8 oz / 1¾ cups all purpose flour
  • 350 g / 12.5 oz / 1¾ cups granulated sugar
  • 1 tsp baking powder
  • tsp baking soda
  • 1 tsp kosher salt
  • 75 g / 2.75 oz / ¾ cup cocoa powder
  • 225 g / 8 oz / 1 cup buttermilk
  • 115 g / 4 oz / ½ cup vegetable oil
  • 2 eggs
  • 1 tsp vanilla extract
  • 225 g / 8 oz / 1 cup hot coffee (substitute same amount of chocolate milk or hot chocolate if you want to make it more kid friendly)

Chocolate Ganache Glaze

  • 115 g / 4 oz / ½ cup heavy cream
  • 225 g / 8 oz / 1 cup semisweet chocolate
  • 1 tsp instant coffee granules (optional)

White Icing

  • 60 g / 1 oz / ¼ cup powdered (icing) sugar
  • ½ tbsp water


Chocolate Cake

  • Preheat oven to 350°F/175°C. Grease and line a 9×13 inch pan with parchment paper.
  • In a medium bowl, sift together the flour, cocoa powder, baking soda, baking powder, sugar and salt and mix until combined.
  • In another bowl, add the buttermilk, oil, eggs and vanilla and whisk to combine.
  • Pour the wet ingredients into the dry and whisk them together, scraping the bowl down as needed. Pour in the hot coffee and continue mixing until smooth, but be careful not to overmix!
  • Pour the batter into the pan and bake for 35-45 minutes, until a toothpick inserted in the center comes out clean.
  • Let cake in the tin for about half an hour, then turn it upside down onto a cooling rack and leave to cool completely.

Chocolate Ganache Glaze

  • Chop the chocolate into pieces.
  • Set a bowl over a saucepan of simmering water (a bain marie), and pour in the cream.
    Add the chopped chocolate and instant coffee granules to the cream.
  • Stir occasionally until all the chocolate melts and the mixture combines and becomes smooth and glossy.

White Icing

  • Combine the powdered sugar and the water and whisk together until thick and smooth. The mixture needs to be barely pourable, and when you lift the whisk out of the bowl the icing should slowly fall off the whisk in a ribbon.
    If your mixture is too thick add a few more drops of water until you reach the correct consistency.
  • Transfer to a piping bag fitted with a small round tip, or with the tip of the bag snipped off.

To assemble

  • Take the room temperature cake and pour the ganache evenly over the top, making sure to cover the whole surface of the cake.
  • Before the ganache glaze sets, pipe the white icing in a tight spiral or in concentric circles over the surface of the ganache.
  • With a toothpick or skewer, start at the center of your spiral and drag lines outwards. Repeat all the way around to create the webbed look.