Place all ingredients A1 into the a mixing bowl and beat at medium speed for 3 minutes.
Add ingredient A2 and beat on low speed for 1 minute or until evenly combined. Pour 650g cake batter into the baking tray (size 12”x 12”).
Bake on 200°C for 15 minutes and set aside to cool.
Hand whisk all ingredients B1 until evenly combined.
Add in ingredient B2 and whisk until evenly combined.
Add in ingredient B3 and whisk until evenly combined.
Divide the cake into two equal parts. Spread chocolate filling on the surface of the first portion of the cake. Stack the 2nd portion of the cake on top. Decorate and cut to your desire shape.