Place the egg yolks, sugar, vanilla and masala in a heatproof bowl. Whisk for 2-3 minutes until the sugar has dissolved. Place the bowl over a saucepan of gently simmering water (the bowl should fit snuggly in the pan, without the base touching the water).
Cook, whisking constantly for 8 minutes until the mixture is thick. Remove from the heat. Place the bowl, uncovered in the fridge, for 30 minutes until the mixture feels cold.
Meanwhile, combine the, espresso and Kahlua in a jug. Roughly chop the savoiardi and scatter them over a large serving platter. Spoon over the Kahlua mixture.
Spoon the mascarpone, double cream and icing sugar into a large bowl. Whisk the cooled masala mixture then add to the mascarpone and cream. Use a balloon whisk to whisk the mixture until it resembles dollop cream (don’t over whisk it should be soft but still hold its form). Spoon the mixture over the savoiardi. Place into the fridge for 30 minutes.
Just before serving, scatter the berries over the espresso cream mixture and serve.
TipTip You can make the Berrimisu to the end step 4 up to 12 hours before serving.
TipTip The traditional, thin sponge finger biscuits are better for this recipe.