Step 1

To make the mascarpone cream, put the egg yolks and ½ the sugar in a bowl and beat with an electric hand mixer until thickened, creamy and pale. Add the mascarpone and mix until incorporated. In a separate bowl, whip the double cream until it forms soft peaks. Add to the mascarpone cream and fold in gently.

Step 2

Beat the egg whites in a clean bowl, add the remaining sugar and whisk with clean beaters until it forms a meringue with stiff peaks. Add ⅓ of the meringue to the mascarpone cream, gently incorporating with a large metal spoon, (try to keep it as airy as possible), then add the remaining ⅔ and repeat.

Step 3

To soak the sponge, first put 3 tbsp warm water into a large bowl (use 5 tbsp if not using sake). Add the matcha powder and mix carefully to get rid of any lumps. If adding sake, mix it in at this stage.

Step 4

Snap 6 finger sponges in ½ and soak 2 pieces at a time in the matcha solution for about 15 seconds. Place at the bottom of 4 glasses, 175-200ml each. Spoon ½ the mascarpone cream on top.

Step 5

Mix the chestnut purée and 1 tbsp sugar until combined, then layer 1 tbsp of purée in each glass. Repeat the layers with the remaining 6 halved and dipped finger sponges and the remaining cream. Sift the matcha powder on top. Cover and keep in the fridge for at least 1 hour, but ideally overnight, before serving.