I never give any parties (I have no guests, a tiny kitchen, a table that seats a maximum of two people, and nothing to celebrate), so if I want to play around with party food, like a fruit salad or a Platinum Jubilee Trifle, I have to make it for my own benefit!

So far as effort goes I'm not sure it's a lot more effort than the suggestion to which this was an alternative, that of cutting a circle out of an ice cream brick to act as a sponge cake filling...