Summer Berry Tiramisu Cake
The seasonal berries and elderflower in this tiramisu cake make this dessert heaven
- 50ml (2fl oz) elderflower cordial
- 85g (3½oz) sponge fingers
- 2 large, free-range eggs, separated
- 50g (2oz) caster sugar
- 1 x 250ml pot full-fat mascarpone
- 1/2tsp vanilla extract
- 400g (14oz) mixed summer berries (we used blueberries, raspberries and blackberries)
- 1 x 20cm (8in) springform baking tin, lined with baking parchment
Mix the elderflower cordial with about 50ml (2fl oz) cold water and soak each sponge finger for a few seconds, until they are just getting soft. Arrange them in the base of the cake tin, packing them tightly. Place the base of a smaller cake tin or a completely flat plate directly on to the sponge fingers and place a bowl full of water on top of that, so that the fingers are weighted down. Chill for at least 30 minutes, but preferably longer.
Place the egg yolks and sugar into a heatproof bowl and, using an electric whisk, beat for about 5 to 10 minutes over a pan of hot water, until the yolks are pale, thick and leave a long trail when the whisk is lifted up. Remove from the heat and whisk until cool. Add the mascarpone to the bowl and beat well to combine. The mixture should be thick and glossy. If it goes a bit runny, whisk it again over the hot water.
In another bowl, whisk the egg whites and vanilla extract together until the whites have formed stiff peaks. Fold a tablespoon of the whites into the mascarpone to loosen the mixture, then very gently and without knocking the air out, fold in the rest.
Remove the bowl and the plate from the sponge fingers, and scatter the berries over them (reserving a few for the top just before serving). Spoon the mascarpone topping on top and refrigerate overnight. Two hours before serving, put it into the freezer. Remove, slice straight from the freezer (a hot knife makes life easier here), then allow the slices to come almost to room temperature on separate plates before serving. Keep any leftover slices covered in the freezer for up to a month.