Preheat the oven to 180C and line two baking sheets with baking paper
2 Finely grind three-quarters of the pistachios in a food processor
Transfer to a bowl and stir in 1/2 cup (55g) caster sugar and flour
Whisk eggwhites until soft peaks form, add remaining caster sugar, then fold into pistachio mixture
3 Place heaped teaspoons on baking sheets and sprinkle with remaining nuts
4 Bake for 12 minutes
Transfer to a wire rack to cool
Dust with icing sugar
