Line a 8x8 container with a parchment paper overhang. While this isn't necessary, it will make removing and cutting the fudge easier.
Place all ingredients in the base of a food processor or blender. Puree until creamy, scraping down the sides as needed.
Pour the fudge into the prepared container and place in the freezer for at least 2-3 hours, or until hard. Remove and slice into 12-16 pieces. Store in the freezer in a freezer-safe container.
Notes
**You can sub peanut butter instead of cashew butter, though note the fudge will have a more peanut taste.