Line the sandwich tins with baking parchment and preheat the oven to 180°C/fan 160°C/gas 4.

Sift the flour, bicarbonate of soda, baking powder and cocoa powder into a large mixing bowl and stir in the caster sugar. In a jug whisk together the eggs, syrup, oil, milk and Baileys. Pour the liquid mixture into the bowl and whisk it into the dry ingredients until they are fully combined.

Divide the mixture between the three cake tins. You can weigh the tins once they are filled to make sure that you have three equal-sized layers. Bake them for 25-30 minutes until they are well risen and a skewer inserted in the centre comes out clean. Leave them to cool for 10 minutes in the tins, then remove them to wire cooling racks to cool completely.

For the icing, whisk the butter and add the icing sugar a few spoonfuls at a time, beating well between each addition. Beat in the Baileys then the cocoa powder and continue beating until you have a smooth and fluffy buttercream.

Place one of the sponges on a cake plate, top with a quarter of the buttercream and use a round-bladed knife to spread it into a smooth layer. Repeat with the other two sponges, putting the top sponge base-up to make sure the top of the cake is flat.

Cover the sides and top of the cake with the remaining buttercream and make it as even and smooth as possible. Decorate with hundreds and thousands, as many as you can fit on, plus all the candles you need. Light them up, blow them out, and enjoy! (You can store the cake in an airtight tin for three or four days.)