Rinse the millet under the running water until the water runs clear. Drain and set aside.
Bring water to a boil in a large pot, then slowly pour the rinsed millet and sweet potato chunks into the pot. Gently stir to blend well.
Continue boiling until the water returns to boil again. Skim the foam from the top. (optional) Stir often so the food doesn't stick to the bottom of the pot.
Turn the heat down to low heat, and let it simmer for about 30 minutes until a softer texture reaches your desired consistency.
Turn off the heat, and serve warm in a small bowl with side dishes. Enjoy!
Notes
If you prefer a thicker consistency, cook a little longer. If you prefer a more liquid texture, reduce the cooking time.
You can also cook millet porridge in the rice cooker or instant pot. Cooking time may vary; please check the manual for details before use.