Bake sweet potato by microwaving it for about 8 minutes, or cooking it in the oven.
Put all ingredients into a bullet or small high-speed blender (a food processor does not get it the dates very smooth). Blend, stir, and blend again until smooth, adding up to 1/4 cup water if necessary to help it blend.
Taste and add maple syrup or other sweetener of choice if desired. I like it as is, but it is not very sweet like traditional frosting. If you'd like a darker chocolate flavor, add up to 1/4 cup more cocoa powder.
The dates thicken it up with time. Store in the fridge. Can be piped as cake decorating frosting, eaten with fruit, or on rice cakes or pancakes.