You need raw pistachios to begin with and for this recipe 140 grams, approximately 1 cup and will need to blanche them to peel fully. This is done by boiling water and placing your pistachios into a rolling boil for 1 minute. Drain and wrap your pistachios in a clean dry tea towel, rubbing to dry and peel most of the skins off. You might have to peel some portions by hand. Place into a blender and pulse, scrapping down the sides until you have a paste and the oils from your pistachios are visible. The pistachios might look like a paste and fine at the stage before the oils become visible, so keep pulsing and scrapping until you see the oils forming on the edges of your blender or food processor. Set your pistachio paste aside where it will keep in a covered and dark space for up to 2 weeks. If you are adding this paste to a dish that doesn’t specify sugar, you can sweeten before finishing up by adding 50 grams / 1/2 cup confectioner’s or icing sugar to your blender once the paste is formed. For further reading re the blanching this information was very helpful and this link was helpful in making the paste.