Passionfruit Sponge | TMix+
Cakes & Bakes

Passionfruit Sponge

Time: 11 minutes in the Thermomix; 20–25 minutes baking
Yield: 1 x 22-centimetre cake, serves 8–10

We call it a classic these days but less than a couple of hundred years ago, the sponge cake was at the cutting edge. The reason? The mid-19th-century invention of baking powder—the raising agent that made it possible for a cake to achieve puffy, airy heights that most cooks could barely dream of in the days when we relied solely on the heated air in whipped egg white to save our cakes from lead-like heaviness. 

This is Lesley Russell’s take on the classic Victoria sandwich. It can be served with a simple filling of cream and strawberry jam and a dusting of icing sugar to finish but we’ve opted for the much-loved Australian twist of cream-and-passionfruit filling and—if you like—passionfruit icing. 

This recipe, which we’ve adapted for the Thermomix from the ever-reliable Australian Women’s Weekly, makes one cake, to be split in half prior to filling. If you have two matching tins—your grandmother probably did, but not all of us do these days—feel free to bake two separate cakes, but if you’re halving the mixture you will need to wind back the cooking time a little.

“Perfect for an afternoon tea with the good china,” Lesley says. “Passionfruit are at their best when they look their worst. Go for wrinkled, shrivelled passionfruit that feel heavy in the hand; they usually have much more pulp inside.”

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Passionfruit Sponge
Ingredients
150 grams self-raising flour
1 tablespoon cornflour
10 grams salted butter
80 grams hot water, from a recently boiled kettle
165 grams white sugar
4 eggs
pulp of 6 large passionfruit
400 millilitres cream, whipped to stiff peaks
150 grams castor sugar, to dust; or additional passionfruit and 2 cups pure icing sugar
Method
  1. Heat the oven to 175C fan-forced. Thoroughly grease a 22-centimetre shallow cake tin, a springform will be fine, and line it with baking paper. 
  2. Place a bowl on top of the Thermomix and activate the scales. Weigh the flour and cornflour into the bowl and set aside.
  3. Using another small bowl, weigh the butter and hot water together. Set aside. The butter should melt into the water.
  4. Place the sugar into the Thermomix and process 2 seconds/Turbo.
  5. Add the eggs and mix 10 seconds/speed 4.
  6. Insert the Butterfly and whisk 10–12 minutes/37 degrees/speed 4 with the MC in place. The mixture should look pale, shiny and have no big bubbles. The mixture should leave tracks if you drag a spatula through it. Meanwhile, sieve the flours together 3 times.
  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/water liquid 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.. 
  8. Pour the mixture into the prepared tin then tap it on the bench a few times to burst any large air bubbles.
  9. Bake in the centre of the oven for 20 minutes or until it feels firm when lightly touched in the centre and is lightly browned on top. Carefully hold the sponge up to your ear and listen; it will be “singing” to you.
  10. Allow the sponge to rest on a wire rack for a few minutes, the “singing” should have stopped, then loosen the edges. Invert onto cooling tray, peel off the paper then flip the sponge back over. Allow to cool completely.
  11. Dust the outer edge of the sponge with castor sugar then split it in two. The best way to do this is with a serrated knife using a deliberate back-and-forth action, making sure you ‘cut’ with the knife rather than ‘push’. Slice only a few centimetres into the sponge half way up the side working your away around the whole sponge. Then continue in the same way working towards the centre until you have sliced all the way through.
  12. Place the lower half of the sponge on a serving plate. Spread the whipped cream over it, spreading it to the edges. Spoon the passionfruit pulp over the cream and gently swirl it through with a spatula. 
  13. Place the upper half of the sponge on top. Cover it with a piece of baking paper then press down with your hand to set the lid in place. 
  14. Dust the top generously with sugar, or make a quick passionfruit icing of ¼ cup of passionfruit pulp mixed to a spreadable consistency with 2 cups of pure icing sugar, or a little more as needed. It is normal (and delicious) when some of the icing drips down the sides. Serve the sponge cut into wedges.

AND … To cut the sponge, use a sharp knife and slice from the outside towards the centre; the sponge will be much more co-operative