Optional: Soak the cashews in filtered/purified water for 30-60 minutes, then rinse and drain. This step is optional but it will make the cashews soft and the mixture extra smooth.
Add all ingredients for the ice cream to a Vitamix and blend until everything is creamy and smooth. Adjust the sweetener to your preference.
Transfer the mixture to an ice cream maker and follow the directions of your machine to make the ice cream.
When it's time to add the "add-ins" (usually after 15-20 minutes or so), add the chopped walnuts and mini-marshmallows. Stir in by hand to make sure they are evenly distributed.
Enjoy immediately with a soft-serve ice cream consistency, or transfer the mixture to an 8 x 5 baking dish, cover tightly, and place in the freezer for 1-2 hours, or until it hardens to the consistency you prefer.