Beat the butter in a bowl until soft. Add the sugar and all the other ingredients up to and including the orange zest, continue to beat until the mixture becomes lighter in colour. Finely grind the pistachios, add to the mixture along with the flour, mix quickly to create a soft dough, flatten a little, cover and refrigerate for approx. 2 hrs.
On a lightly floured surface, roll out the dough in batches to approx. 7 mm thick. Cut out the hearts and place on a baking tray lined with baking paper.
Bake for approx. 8 mins. in the centre of an oven preheated to 180°C. Remove from the oven, transfer to a cooling rack with the baking paper and leave to cool.
Melt the glaze as per the instructions on the packet, stir in the turmeric.
Dip one half of the pistachio hearts into the glaze, sprinkle with pistachios and leave to dry.