Step 1

Chocolate cakeGrease a quarter-sized sheet pan (9 x 13 inch / 23 x 33 cm) and line with baking or parchment paper, ensuring two sides of the paper overhang.

Step 2

Preheat oven to 180 C (350 F) standard / 160 C (320 F) fan-forced. Boil the kettle and pour out 1/2 cup water and set aside.

Step 3

In a large mixing bowl, beat butter and sugars with an electric mixer on medium speed for 1-2 minutes or until creamy and combined.

Step 4

Add vanilla and eggs, one at a time, and continue to beat until combined. Take a moment to scrape down the sides of the bowl.

Step 5

In a separate bowl, sift flour, cocoa powder, baking powder, baking soda and salt and lightly whisk. Add the dry ingredients, along with the hot water and gently mix on low speed.

Step 6

Add sour cream and mix on low speed until cake batter is smooth and creamy.

Step 7

Pour chocolate batter into your prepared pan and smooth out into one even layer.

Step 8

Bake for approximately 35 minutes or until a skewer inserted into the middle of the cake comes out clean. Leave the cake to cool for about 15 minutes before carefully transferring to a wire rack to cool completely.

Step 9

Chocolate frostingPlace butter in a large mixing bowl and beat with an electric mixer on medium speed until pale and creamy.

Step 10

Meanwhile, melt chocolate in the microwave, stirring every 20 second, until smooth and set aside to cool slightly.

Step 11

Add half the sugar and the sour cream, and beat on low until the sugar is incorporated. Then, add the remaining sugar and beat on low until mixture is smooth and creamy.

Step 12

Next, add melted chocolate to the buttercream, ensuring the chocolate is still smooth and melted but not warm. Beat on medium speed until chocolate buttercream is smooth and creamy.

Step 13

Gently cover your cooled cake with chocolate frosting. Then scatter candy pieces on top.