Prick sweet potato several times with a fork. Wrap potato in a damp paper towel. Microwave on 100 percent power (high) for 3 minutes. Turn potato over; microwave for 2 to 3 minutes more or until tender. Cool slightly. Remove and discard peel. Mash potato with a fork; measure 1/3 cup.
In a blender combine the 1/3 cup mashed sweet potato, almond milk, brown sugar, coffee crystals (if desired), and 1/8 to 1/4 teaspoon ground cinnamon. Cover and blend on high speed for 1 minute. Strain through a fine-mesh sieve into a small saucepan. Cook and stir over medium-low heat until heated through. Transfer to a heat-proof mug. If desired, sprinkle with additional ground cinnamon and garnish with a cinnamon stick.