Cook the sweet potato. - Peel and cube the sweet potato, then add it to a pot of boiling water. Let it cook for 15-20 minutes, or until tender. Drain the water and mash the sweet potatoes with a potato masher or fork until smooth. - Make sure not to overcook the sweet potatoes, as they can become mushy and lose their flavor.

Blend the cocktail base. - Add the mashed sweet potatoes, heavy cream, milk, cinnamon, nutmeg, and maple syrup to a blender. Blend on high for 30 seconds, or until smooth and creamy. - If you prefer a thinner consistency, feel free to add more milk.

Add the whiskey. - Pour the blended cocktail base into a large bowl. Add the whiskey and stir until the ingredients are well combined. - If you are not a fan of whiskey, consider using a non-alcoholic whiskey alternative such as Ritual Zero Proof Whiskey Alternative.

Serve the cocktail. - Divide the cocktail evenly between 2 serving glasses. Garnish with a sprinkle of cinnamon, if desired. Enjoy! - For a fun twist, serve the cocktail in a hollowed-out sweet potato skin instead of a glass!