You can make all components of this passionfruit cake ahead of time! The curd can be made 1-2 days in advance and stored in the fridge in an airtight container. I've also had success with freezing passionfruit curd for up to a month and thawing it in the fridge. The cake layers can be made and stored at room temperature, wrapped in plastic wrap, for up to two days. They can also be frozen for up to 2 months, wrapped well in plastic wrap and heavy duty foil. The white chocolate Swiss meringue buttercream can be made a day or two in advance as well. Just store it, covered, in the fridge, and on the day you'll be using it, allow it to sit out for a few hours to come to room temperature. Then use a stand mixer or hand mixer to beat the buttercream to bring it back to that silky smooth texture. And it's ready to use on your passionfruit cake!