Put the hazelnuts in a food processor and process on the highest speed for 10-15 minutes, stopping to scrape down the sides of the bowl at regular intervals, until you have a smooth nut butter.
Meanwhile, place the dates in a bowl with the boiling water and leave to soak for 10 minutes.
Add the dates and water, along with the remaining ingredients to the food processor with the hazelnut butter. Process the mixture on high until it is smooth. Transfer to a jar and store for up to 1 week in the fridge.