First, toast your pistachios by putting them in a pan on medium heat until they smell toasty. You can toast them in the oven too, on 170℃ for 7-8 mins while stirring half through.
Blend them in your food processor until pistachios release all their oil and become a paste. Stop your food processor and scrape down the edges when needed (it takes about 8-10 mins).
Add the honey and salt, pulse until incorporated.
Store in an airtight container in the fridge