Method:

• In a food processor fitted with a metal blade, add ½ cup of the pistachios, ¼ cup of the flour and the corn flour. Pulse until finely ground.
• Very roughly chop the remaining pistachios. Set aside until needed.
• Sift the remaining flour with the baking soda and salt.
• In a bowl of a stand mixer, beat the butter and sugars until creamy. Add the egg and vanilla. Beat until combined. Add the sifted flour and the ground pistachios. Mix just until all ingredients are moistened. Stir in the chopped pistachios.
• Line a baking tray with greaseproof paper. Take about 2 tablespoons of the mixture and shape into a ball. Wetting your hands will make this process easier. Place each cookie ball in the baking tray. You don’t need to space them apart just yet. Continue until you shaped all the cookie mixture. I usually make about 20 cookies.
• Now this is important: Place the tray in the fridge for 1 hour. This will set the butter and will help bake the cookies bake more evenly (see note).
• Preheat oven to 160° C fan. Line baking trays or cookies sheets with greaseproof paper or silicon mats. Place cookie balls on the trays spacing them about 5 cm (2 inches) apart. Bake cookies for 15-17 minutes until they are golden around the edges and soft in the centre. Cookies will seem very undercooked and soft when you take them out of the oven but don’t be tempted to bake them longer. They will firm up as they cool. Transfer soft cookies on wire racks to cool.