When the mixture is cold, place it in an ice cream maker and process according to the manufacturer's directions. Process and then mix in the chopped walnuts. Place in a parchment lined pan and freeze. It will have texture of soft serve ice cream at first, but hardens up after a little time in the freezer. If it's too hard to scoop when you take it right out of the freezer, let it sit on the counter for 10-15 minutes.
Recipe by Plant Craft at https://www.rachelcarr.com/chocolate-reishi-walnut-ice-cream/