* 180g (6½oz) self-raising flour
* 1 tsp baking powder
* 1 tbsp matcha
* a pinch of sea salt
* 180g (6½oz) unsalted butter, softened
* 180g (6½oz) caster sugar
* ½ tsp vanilla extract
* 3 large eggs
* 100g (3½oz) pistachios, chopped
For the white chocolate frosting:
* 300ml (10fl oz) double cream
* ½ vanilla pod
* 100g (3½oz) white chocolate, chopped
1. Make the chocolate frosting. Put half of the cream in a pan. Cut the vanilla pod in half lengthways and scrape out the seeds into the cream, and drop in the pod.
2. Bring to just below the boil then remove from the heat, remove and discard the used pod and whisk in the chopped chocolate until smooth. Cool then place in the fridge and leave to chill for about an hour.
3. When the frosting’s almost ready, preheat the oven to 180°C/350°F/gas mark 4, and line two 12-hole cupcake tins with 24 paper cases. In a bowl, sift the flour, baking powder, matcha and salt together.
4. In a separate bowl, beat the butter, sugar and vanilla together until very smooth. Add the eggs one at a time, adding some flour halfway through, if necessary, and beating well after each addition.
5. Fold the flour mixture into the egg mixture along with three-quarters of the chopped pistachios (keep the rest for decorating later on).
Spoon the cupcake mixture into the cases and bake for 15–20 minutes or until risen and slightly golden.
6. Remove the cupcakes from the oven and transfer to a wire rack to cool for five minutes, then remove from the tins and leave to cool completely.
7. In another bowl, whip the remaining cream until it reaches soft peaks. Beat in one-third of the whipped cream into the chilled chocolate cream mixture and then fold in the remainder.
8.Transfer to a piping bag ready for decorating the cupcakes. Pipe the frosting onto the cupcakes, spread a little with a knife and then top with a sprinkle of the remaining chopped pistachios.
More from Book of tea:
The Book of Tea: Growing it, making it, drinking it, the history, recipes and lots more by Nick Kilby and Louise Cheadle is published by Jacqui Small, £20.