Preheat oven to 180°C/160°C (fan-forced). Grease two x 20cm diameter round cake pans. Line bases and sides with baking paper, extending paper 3cm above pan edges
Place 4 of the eggs in a large bowl of an electric mixer. Using the whisk attachment, beat for 5-6 minutes on high speed, until very thick and pale. Add half the sugar, 1 tbsp at a time, beating between each addition. Beat in half the vanilla
Sift half of each of the flours, twice onto a sheet of baking paper then sift again over egg mixture. Add 1 tbsp boiling water. Gently fold to combine. Do not stir. Divide evenly among prepared pans
Bake for 20-22 minutes, or until golden brown and sponge slightly shrinks away from pan sides. Immediately turn out onto a wire rack lined with greased baking paper. Allow to cool
Repeat Steps 2, 3 and 4 with remaining ingredients to make two more sponge cakes, making four cakes in total
To make frosting, place chocolate in a large heatproof bowl. Sit bowl over a saucepan of simmering water. Stir until melted and smooth. Remove. Cool for 10 minutes
Beat butter in a large bowl of an electric mixer until pale and creamy. Add chocolate and beat until combined. Beat in milk. Gradually add cocoa and sugar, beating until smooth
To assemble, place one sponge cake onto a serving plate. Spread with ⅓ cup of the frosting. Using a 9cm round cutter, cut out the centre from two of the remaining sponge cakes. Sandwich together, with ⅓ cup of the frosting and place on top of sponge cake on plate. Fill hole with M&M’s.
Spread ⅓ cup of frosting over top of cake and invert remaining sponge cake on top to enclose M&M’s. Spread remaining frosting over top and sides
Coarsely chop ⅓ cup of M&M’s and press onto frosting around the base of cake. Scatter 1-2 tbsp over the top of cake. Refrigerate until required
Tips & Hints:
Sponge cake is best served on day of being made
Use fresh eggs at room temperature
Don’t skip on the sifting process! This incorporates air which is essential for a good rise
For the best results, gently sift the sugar and flour onto the egg mixture when making the batter to preserve as much air as possible
Ensure the baking paper is greased, this will prevent it from sticking, when turning out the sponge
Use any candy or popcorn to fill cake.
Sponge cake cut-outs can be frozen and enjoyed at a later stage or simply top with whipped cream, jam and fresh berries
I love this!! My mother always made my and my two brothers birthday cakes from scratch -- every year. I am now 66 years old and one of my most memorable cakes she made is this one. It is just too much fun when you cut into it.