Tiramisu Swiss Roll
Ingredients:
Coffee sponge:
1-2 tbsp sunflower oil for greasing the baking sheet
8 g instant coffee granules
20 g full-fat milk
3 medium eggs, room temperature
125 g caster sugar
1 tsp vanilla bean paste (or 2 tsp vanilla extract)
45 g unsalted butter, melted
80 g plain gluten free flour
3/4 tsp Xanthan gum
1/2 tsp baking powder
1/4 tsp baking soda
1/4 tsp salt
Mascarpone whipped cream filling:
250 g mascarpone cheese, cold from the fridge
160 g double cream, cold from the fridge
60 g icing sugar, sifted
1 tsp vanilla bean paste (or 2 tsp vanilla extract)
Coffee soak:
4g instant coffee granules
12g caster sugar
45g hot water
For assembling the Swiss roll:
1-2 tbsp icing sugar
For decorating the Swiss roll:
1-2 tbsp cocoa powder
chocolate shavings, for decoration
Method:
Coffee sponge:
Pre-heat the oven to 180C and line a 25x38cm rimmed baking sheet with parchment/baking paper. Lightly grease the parchment paper and the sides of the baking sheet with oil.
Mix the instant coffee granules with the milk and heat them (either in the microwave or on the stovetop) until the mixture is hot and the coffee is fully dissolved. Set aside to cool until warm or at room temperature.
Using a stand mixer fitted with the whisk attachment or a hand mixer fitted with the double beaters, whisk the eggs and sugar together until pale, thick, fluffy and about tripled in volume (the ribbon stage). This should take about 5-7 minutes on a high speed setting.
Add the coffee-milk mixture, vanilla and melted butter, and whisk briefly until combined.
In a separate bowl, sift together the gluten free flour blend, Xanthan gum, baking powder, baking soda and salt. Add the dry ingredients to the egg mixture and whisk well for about 15-30 seconds until no flour clumps remain. Scrape down the bottom and sides of the bowl to prevent any unmixed patches.
Transfer the batter into the lined baking sheet and smooth it out into an even layer. You can tap it a few times on the counter to make it perfectly level and also to get rid of any large trapped air pockets.
Bake for about 10-12 minutes or until well risen, soft and spongy to the touch, and an inserted toothpick comes out clean.
Immediately out of the oven, cover the baking sheet with a large sheet of aluminium foil (this traps the moisture within the sponge, making it more pliable and flexible). Allow to cool to room temperature or lukewarm – ideally, the temperature of the sponge shouldn't drop below 22C.
Mascarpone whipped cream filling:
You can prepare this filling using a stand mixer fitted with the whisk attachment or with a hand mixer fitted with the double beaters. Combine all the filling ingredients in a large bowl (or the bowl of a stand mixer, if using) and whip them to very soft peaks.
Coffee soak:
Mix together the coffee granules, sugar and hot water for the "coffee soak", until the coffee and sugar are fully dissolved. Allow to cool until warm or at room temperature.
Assembling the Swiss roll:
Once sufficiently cooled, gently loosen the sponge from the edges of the baking sheet with an offset spatula or a thin knife. Lightly dust the top of the sponge with powdered/icing sugar, to prevent sticking. Turn it out onto a large sheet of parchment/baking paper, so that the caramelised “skin” side is facing down (so that it’s on the outside of the Swiss roll when you roll it up).
Peel away the parchment paper that used to line the baking sheet. Use a pastry brush to gently brush the sponge with the coffee soak. You might not need all of it – don’t over-soak the sponge, as that can make it too fragile.
Spread just over half of the mascarpone filling evenly across the sponge, all the way to the edges.
Turn the sponge so that a short edge is closest to you. Using the parchment/baking paper underneath to help you, roll up the sponge until you get a 25cm long log.
Use the remaining mascarpone filling to cover the outside of the cake. At this stage, I recommend chilling the Swill roll overnight (or at least for 1-2 hours) before serving, to achieve both the best flavour and texture.
Just before serving, dust the Swiss roll generously with cocoa powder and sprinkle on some chocolate shavings.