To make the spiced meringue buttercream, set a heatproof bowl over ... Roll the cake up into a tight Swiss roll, transfer to a baking tray and chill in the fridge for 15 minutes.

For Italian or Swiss-style buttercream, whisk molten sugar (heated to the soft ball stage, 112-116C/234-240F) into whisked egg whites. Whisk the fat into the meringue mixture as it cools – the ...