Line a 9 by 13-inch baking dish with parchment paper and leave flaps hanging over the side of the dish for easy removal.
In a saucepan over medium-low heat, combine the maple syrup, coconut sugar, and coconut oil. Stir until the coconut sugar melts and the mixture is liquid, about 5 minutes.
Whisk in the cashew butter, arrowroot powder, vanilla, salt, and chocolate and continue stirring over low heat until the chocolate melts and everything is well blended, about 5 minutes more.
Pour the fudge into the prepared baking dish and smooth the top with a rubber spatula. Chill in the refrigerator until set, about 6 hours.