While on fixing failures, in our latest issue (Spring/Summer) we included Lesley Russell's delicious recipe for a foolproof sponge—this one including a luscious passionfruit cream—after many requests.

Unfortunately a fool (me) was involved in the production, and we omitted a key moment in the method: when to add the butter/water mix. My apologies for the error.
The current version is online at tmixplus.com. For those who can't be bothered clicking through, here's the correct step:

7. The key to sponge is to not over-mix it. Remove the lid then sieve the flour on top of the egg mixture. Replace the lid and trickle the melted butter/waterliquid through the lid, and mix together at speed 1 until the flour and butter mix is incorporated, about 15–20 seconds. Remove the Butterfly and fold in any unmixed flour gently with a spatula or with your hand.