Bring a medium sized pot of water to a boil and add the shelled pistachios. Let them boil for 3 minutes, then drain and place on a clean kitchen towel.

Fold the towel over to cover, and rub pistachios in the towel to loosen the skins. Separate the pistachios and discard the skins. Add the pistachios to the blender.

Add the butter and 1/4 cup milk to a small microwave safe bowl. Heat in 20 second bursts, just until butter is melted and milk is hot. Add white chocolate and stir until melted. If it needs more melting, heat for another 10-15 seconds and stir (you can also do this on the stovetop in a small saucepan on low heat).

To the blender with the pistachios, add the remaining 1/2 cup milk, powdered sugar and salt. Scrape in the melted white chocolate/butter mixture. Pulse on medium speed until the pistachios turn into a paste. You’ll need to stop the blender 3-4 times to scrape down the sides. Blend on high power for 30 seconds to a minute, until texture turns smooth and creamy. Once the mixture is ready, transfer to an airtight container and refrigerate until ready to use. The pistachio cream will keep well in the fridge for 2 weeks