Preheat the oven to 180°C. Spread the pistachios out onto a lined baking tray and bake for 10 minutes until lightly golden.
Transfer into a blender or processor and blitz until it becomes a fine meal. Use a spoon to scrape down the sides as needed and then continue the process until the nuts release their natural oils. It should eventually become a smooth and runny paste. This can take anywhere between 10-30 minutes depending on your appliance.
Transfer into a clean airtight jar. Enjoy on toast, in desserts or by the spoonful.
