Preheat oven to 170C / 340F / 150C fan forced. Line 2 baking trays with baking paper.
Beat together the butter and sugar until light and fluffy.
Sift together the flour and rice flour, then add to the butter and sugar in 3 lots until fully incorporated.
Add the zest and chopped pistachios and mix until well distributed.
On a lightly floured surface, knead the dough with your hands until it all comes together. Roll between two sheets of baking paper to about 1cm thick. Cut out shapes (I used a square cutter approximately 4cm wide). Use a spatula to help to transfer the unbaked cookies to the baking trays and sit them at least an inch apart.
Bake for around 18-20 minutes until just starting to turn golden on the edges.
I use a standard Australian 20ml tablespoon (4 teaspoons worldwide)